I'll chip in with another perspective real quick as I take a brief break from studying:

Honestly? I don't really care too much, if at all, about recurring motifs in characters. I'm actually super apathetic to other people's OCs, and not really for the reason of me being the most self-centered guy on earth(even though I am), but more for the reason that I have no guarantee how long I'm sticking around other people. CSes more often than not fall into several trappings, including my own on more than a single occasion(and a friend's given me insight in how I distinctly make one of three archetypes worth of characters usually). I'm not really here to go all "REEE" at CS quality though; it's more to say that the core concept for a character barely interests me, if at all, when it comes from another person. The exception to this is when the concept is beyond cool, making me unable to look away, or so bad I can't look away for different reasons.

"But Ammokkx, if you don't care about other people's characters, why are you RPing?"

Good question. Idk myself. But if I had to try and give an answer: Through the course of the RP, I usually start caring once the characters in question get going and rolling and engaging with others. Only once the dynamics of the cast start to settle in place, do I start seeing the other characters as actual entities rather than temporary nuisances before the RP's untimely demise. Therefor, I also barely look at what external gimmicks a character may have. To me, characters are no more than a voice in a room. Unless it is something you can absolutely not get around, such as being wheelchair bound or interacting with a blind dude, my characters are about as indifferent as I am on the subject. Even in the aforementioned two cases, unless the RPer makes a note to remind you of those facts at every turn, I'm prone to just skim over it and treat the other character as just about anyone else, only paying special attention to the fact if a situation were to come up in which it is relevant again.

I just care much more about a character's actions rather than a character's nature. Usually, unless I'm in a Gming position, this just means that I skim other people's sheets at best and only read them more thoroughly once an actual interaction happens IC.

I'd say I've gotten more 'generic' in my characters the longer I've RP'd, too. While in the past I wasn't shy of going with 30 something gruff dudes(no old ladies tho; only once did I get a chance to play an adult vampire woman), now I'm more prone to just playing 16-18 y/o teens in settings fit for 16-18 y/o teens. Whether that's because I've become more of a weeb over time or because I've not had an original RP concept allowing for older characters stick out to me, remains to be seen. Since a character, to me, is so unquestionably defined by their role in the RP proper, I've also gotten more vague on CSes as I await the day to play them IC.

Ironic, then, that almost all of my favorite characters are more concepts than they are execution. Granted, 3/4 had some basic relations blooming in their short-lived RP which are the foundation of this favoritism, but I didn't get to go much in detail. The 4th, then, is one that never even hit the IC, and is to this day, still a complete 'what if' where I just went all-out with designing her gimmicks in the character sheet.