Back in the day I was a participant of a particular campaign here on RPOL that (I personally believe) was somewhat legendary in its scope and style. For the most part, the quality of the players and the GM in particular set an extremely high bar for me, one which few if any other games have managed to measure up to.

I'm happy to say I was at least witness to the campaign completing on the sidelines, though no longer a participant, and for a very specific reason: I ended up hating my own character.

He was a challenge to begin with. At the time of joining, I wasn't very experienced with non-Freeform RP, though I understood the universe and the game's mechanics, my own maturity level left something to be desired after a while and this unfortunately reflected on the character as well through my writing and RP. While he injected a certain aggressive "energy" to interactions with other party members, and even managed to be loved to some extent, or so it seemed, I won't deny that this character must've been difficult to deal with for my fellow players and my (infinitely patient) GM.

The end result was me flagging out of this wonderful campaign, both from life-things happening as much as me simply being tired of the character himself. I saw potential in him, he could've moved beyond what he'd ended up as my participation waned, but I just didn't have it in me. I loved him, but didn't love him enough to care. I loved the campaign and my fellow players, but couldn't muster up the energy to continue.

Interestingly, this character in particular has become something of a representation for my "Ur-Character" in my other writing, a hero who begins as a flawed menace only to transcend and become something more - the "hero's journey" in a nutshell, I suppose. Perhaps there is some love there, after all.

Am I alone here? Have you ever created - and played - a character you ended up hating?

That has happened to me as well. I raised the issue with the GM and changed to a new character at the first convenient moment. No one should have to play a character they don't like, or be sidelined if they don't like their character.

I've made some characters that I wound up just not being able to get into, but never one I hated. I've played with people who hated their characters, though, and I can safely say that the worst possible outcome is that player who absolutely loathes their character, but also absolutely refuses to change that character out for another one 'because they've put too much time and effort into the first one'. The end result of that almost invariably winds up being someone who doesn't want to play, doesn't play, and then drops the game, leaving the GM to have to NPC their character.

If you don't like or enjoy your character, speak up. If the GM gives you a chance to change out of a character you don't like or enjoy, take it.

I won't say "hated", but I have had characters that wouldn't develop. I'm not sure that I can pinpoint why they didn't develop. It might have been me. It might have been a limited concept. It might have been that the character didn't fit with the game and/or party. All that we can do, as engine said, is work with the DM to replace the character or to force a change (i.e. lifted curse, Helm of Enlightenment, opposite twin, etc.) :)

It is worth highlighting that there is a difference between a character you can’t get into and one you don’t like as a person. The latter can be enjoyable, but the former should be ditched ASAP in favour of another concept. Playing a complete fruitknuckle can be fun, provided the GM and other players understand you are acting a role, not being your own self!

No.  I've ended up with Characters I've found boring (which can be shifted into fun again with some work) and Characters in conflicts with other Characters that made group play untenable, but I've never hated any Characters I've made.

You can always turn into something you like better. Any incident really can be the catalyst for change. I've had characters start one way and I didn't like that direction so I would work with another player to get into a fight or something that would make him readdress things.

Heck in one game I asked the GM if my guy could get mugged and as he sat in the pool of blood after driving away his party in a big fight he suddenly began to rethink how he treated those around him...

I've never actually hated a character that I've created, but I have a few times created a character that I can't really role play.   It's a tough call when it's time to put aside an idea, perhaps in favor of something that works better for you.

Never created a character that I ended up hating, no.  I've created several characters which were not as much fun to play as I had expected, but that was long before I got onto RPOL.  I'm highly selective of which games I even RTJ, and if I read a game description that doesn't spawn at least some kernel of an enjoyable character right away, I'll usually not even bother with the RTJ (not always...there was a Middle Earth-set game that I joined where I was there, initially, strictly because of the setting...didn't settle on a character concept for several days after actually joining the game.  I have to say, because of that character, I ended up re-reading The Silmarillion and it was like reading it for the first time, for me...I got so much more out of it than I ever had before.)

Most of the time, I know pretty quickly whether or not I'm going to enjoy a character...the few times (on RPOL) where I've skirted the line with an 'iffy' (for me) character, the game itself hasn't lasted long enough for me to get tired of the character.