You would think 開く (open) would take a る, but perhaps it's a little insecure, so it only takes a く.

洗う (wash) is a softer kanji. It takes the う ending because of this type B personality. 洗う and 歩く (walk) are friends. 歩く is more outgoing than 洗う. 歩く takes the slightly stronger ending, く, but still く is not a very strong ending. It does not have the prestige and ego that る has, and る is not so prestigious as す, the ending of the truly elite. Anyway, 歩く gets the く ending; and although he's more outgoing and aggressive than 洗う, both 歩く and 洗う are not treated with the utmost respect by the other kanji (not to say that they are mistreated or anything, just lower class).

遊ぶ (play) is an odd kanji, so it takes the ぶ ending. Its pronunciation, “あそぶ,” is an odd friend group: あ and そ together as friends brings out the latent weirdness of both of them. It makes sense that they would complete their trio with another strange guy like ぶ. “Play” as a word in English is a bit odd too in terms of alphabetic relations and personality. I believe “play” and 遊ぶ would be friends given the opportunity.

選ぶ (choose) is another weird one who gets the ぶ ending. You can tell by both his kanji and pronunciation. With his pronunciation “えらぶ,” he's starting with the sort of unusual え who you don't see so much and ending with ぶ. The pronunciation makes me think of “Arab.” I think 選ぶ is a boy in his early to mid 20s. Not a trouble maker or annoying, more like a tolerable but less easy going skater type. Often shocked by life's absurdity and sort of incredulous.

会 (meet) is a “main character,” but he is humble and more mature than a lot of other MC kanji. He takes the humble う ending because of this nature. 会う is a male. 違う (wrong, differ from) is also a male. He's a bigger man and you would think by looking at him that he'd be aggressive and take the く ending, but he's a gentle giant and takes う. You can tell he's not the classic macho man because of his pronunciation “ちがう”. Impulsive ち plus enabling instigator が. Sometimes I think of him as a little gay man though, depends on the context.

出す (take out) gets the す end because he's an MC kanji. An L5 and probably one of the first you'd learn. A straightforward kanji that looks like what it's describing. He's cocky.

吹く (blow) and 降る (fall from the sky) both have kanji readings of ふ. 吹く is the weaker kanji however, so it gets the く ending rather than distinguished る. 降る takes the る ending, but she isn't arrogant. Both 吹く and 降る are quiet. They're kind and feminine. 降る hopes that 吹く isn't upset that she gets the る ending and 吹く doesn't. 吹く isn't upset. Even if she was, she wouldn't say anything because she's shy.

入る (enter) is an MC thus the る ending. 入 is an arrogant girl, somewhere in her 20s or 30s. She knows she is important. She's not vindictive or entitled though, just a bit annoying and a little immature. The pronunciation “はいる” has got the affirmative はい, which is kind of fitting.

履く (put on (lower body) clothing) is a slightly crass verb. Not really, but for its association with the lower body it gets the く ending.

話す (speak) has prestige as a classic kanji, so it gets the す ending. 言う (say), however similar, gets the wear う ending. Since lots of kanji contain 言 within them as a radical, including 話, you'd think 言う would be the more “prestigious” one over 話す, but for whatever reason it gets the う ending and 話 gets す. Perhaps 言 is being passively treated poor by the fact it was given う (treatment by the higher ups or whoever came up with this).

払う (pay) is unlucky in that it was given the う ending. He's not weak natured or anything, just unfortunate.

張る (affix) has got 弓 (bow) and 長 (tall), both strong components, so he gets the る ending. A serious older man, perhaps feels slightly responsible for younger 履く.

走る (run) is quicker than 歩く so it gets the more prestigious る. Like an older brother.

働く (work) has strong and stoic, masculine energy. A hard working laborer. He deserves the る ending but doesn't want it. He'll take nothing over the working class く.

引く (pull) also takes the く ending. 引く is much younger than 働く and he's more jaunty, but he's a blue collar worker as well, so he has the く ending.

行 is one of the main-est characters, but he doesn't take す because he's weird. He doesn't want it. 行く (go) is young and associates with characters like 働く and 引く more than other す verbs, so he likes his く ending.

かぶる (put on one's head) and かかる (take (a resource), hang) are both (usually) written using kana only. They are confident and kind of entitled which is why they take this form. They both have る endings and the prestige from that may be what's causing them to be so showy and only use kana.

帰る (return) and 返す (return something, restore) are grouped together because they have the similar reading “かえ_” but they're very different personality wise. 帰る is serious and he doesn't like 返す that much but he puts up with him because they're always together. Even though 帰る is slightly older and more responsible than 返す, he only gets the る while 返す gets the す end.

書く (write) is another important “main character” kanji, but she doesn't get the す ending. She gets the working class く instead, but so do other important kanji like 聞く (listen), 開く, and 行く. They're all kind of in their own group of common kanji who use く endings.

買う (buy) is similar to 言う in that he has prestige, but still gets the う ending. They're both getting shafted. 買う doesn't really care though. He doesn't like it, but he doesn't really care. 言う kind of cares, but she's more sensitive than 買う. Often 買う just wants to get his usage over with so that he can go back to being abstract, untethered by context.

消す (extinguish) is young and thinks of himself as an important verb due to the fact that he has the す ending. He also thinks he's cool because his pronunciation has け.

聞く (listen) pronounced “きく” makes me think of the musical artist Kikuo. He gets the く ending like other verbs 書く, 開く, 行く. Somewhat close to 書く, but their friendship is an interesting one because 聞く is heiban, so he's more mainstream, whereas 書く is akamadaka.

切る (cut) pronounced “きる” sounds like “kill you,” with a knife perhaps? He's young and looked down upon, but he just keeps to himself, so there's no real reason.

困る (to be in trouble) is nakadaka on 2. There's a little something off with him, but he manages to get along fine in society. He's a caged tree. I just kind of remember this one.

込む (to become crowded) pronounced “こむ” reminds me of 公務員, “こうむいん.” Crowded like a bunch of civil servants on their way to work.

曲がる (bend), 上がる (go up), and 下がる (go down) all have the same ending “_がる,” just different first letters and pitch accents. All of them are talking about movements in directions. 曲がる and 下がる are male and 上がる is a female. 上がる and 下がる are around the same age/maturity (late 20s/mid 30s—it's hard to pinpoint exactly) and 曲がる is younger (early 20s). Since 曲がる and 上がる are both heiban, they group together. 下がる is the outcast, though he is not a weirdo, he's just treated as such by elitist 上がる and her crony 曲がる.

待つ (wait) “まつ” is similar to 持つ (hold) “もつ.” They have similar kanji, the same ending, both have an M letter, both are atamadaka. 待 contains radical “step” and 持 has radical “hand.” That makes sense for their meanings. You could say they are friends.

磨く (polish) pronounced “みがく” is weird because he has みが-. I remember he's weird, then I think “why is he weird?” and then I just have to remember it's because he has the みが- combination. The みが combination is kind of like A and G on a piano. が is the older girl (G) and み is the younger girl (A). Not exactly, but a little bit.

治る (get better) pronounced “なおる” has the る ending. 直す (fix) and 治す (cure) are both pronounced “なおす” and have the す ending. 治す with す end happens to someone else (it seems to me) and 治る happens to the self by the self (it seems to me). For this altruistic reason, 治す gets the prestigious す ending. 直す and 治す are closer to each other than they are to 治る due to the fact that they have the same ending, but they are not mean and don't exclude 治る. Both verbs with 治 are female and 直す is a male. All of them are nakadaka on 2.

並ぶ (stand in line) and 習う (learn) differ in pronunciation by only their ending and pitch accent. 習う gets the lowbrow う ending, though what it describes (learning) is quite valuable. It also gets the nakadaka 2 pitch accent. Meanwhile 並ぶ, which gets the obscure (but still more prestigious than う) ぶ ending, gets to be heiban.

上る (climb) despite its reputable kanji and heiban pitch, is a bit of a weirdo. Its pronunciation “のぼる” has ぼ and の, both kana with sort of weird personalities.

乗る (board) is like Patrick Bateman. Self important, vain, easily irritated, yuppie る-ending and heiban pitch. He's quite serious as opposed to some of the other N-pronounced kanji. I find 乗 very fun to write, though.

脱ぐ (undress) is a little freak. He has the bizarre ぐ ending, a bizarre kanji that looks like an alien TV, and a pronunciation with outsider kana ぬ. Really, he's not so crazy, but like 履く he's one who might be avoided by the others due to his meaning.

塗る (paint) is a fashionable woman or at least a woman who considers herself fashionable to some degree despite having the arguably unfashionable ぬ pronunciation. Maybe regarding that she feels like she has something to make up for, so she showcases the る ending whenever possible. 盗む (steal) is the opposite. His pronunciation being “ぬすむ” gets him a spot right next to 塗る and—if you squint—they have similar kanji. These things give 塗る a complex and a need to look down on 盗む to reaffirm her status, however 盗む is undeserving of most negative judgement he receives. Despite his meaning, he isn't a bad guy. He has a whole group of “outcast” kana who, when together, I think would rather have fun than cause trouble.

置く (put) is an important word. It has an important meaning, so he has the important お reading. “おく” is straight forward. It makes sense. No time for the る ending. He'd be ok if that was what he was given, but it wasn't, so he's fine with just く. Sometimes I think of the color orange when I see this kanji.