What retcons do you least like?

[Tzigone]

Can be ordinary retcon or universe reboot. I'm particularly talking about ones that stuck around a while, rather than those that were quickly reversed.

Black Canary is Black Canary's daughter. And half Ollie's age. Ooh, I hated this one with a fiery passion. I really did enjoy her storyline about her widowhood and dealing with that loss in the bronze age. And I liked bronze age Ollie and Dinah (except for one writer, mostly). They already made it kinda icky with the age gap and him crushing on her mom (IIRC), and then it just went down the tubes as (IMO), Ollie's character was ruined.

Roy being a child and kicked out of house and made homeless for drug addiction. Which again ties in to the continuing jerkification of Olllie.

Diana is Zeus' child. This is one not major to me, just a minor, niggling annoyance. For a character whose start was about women, a female society, female accomplishment, etc. it is extremely frustrating to have her power (a defining characteristic) come from the male parent. Likewise, it frustrates me when the society is rewritten as "bad." I don't want Hercules (half-brother because of Zeus) as a good guy, friendly with Diana. That really doesn't work for me at all, given the golden age setup.

Krypton is a pretty unpleasant place. Making the society less admirable would not so much have been an issue, except somewhere along the way, they did this with pretty much every fictional society we had a hero come from. They all come up inferior to our own earth-based society (at least in USA). And now we've also seen at least Jor-El, Zor-El, and Allura as evil at some point. Not sure about Lara. Not happy about that, either.

Batman's misery back-projected. Year one, of course, worked with this. And post-crisis greatly increased the rift/issues between Dick and Bruce, but had Bruce 99% responsible, instead of the more nuanced and understandable (though still at fault) way of pre-crisis. And had him doing a great disservice with the way that he took Jason in, post-crisis. And resetting him to basically have no respect for his JL colleagues. And it's just continued and gotten worse and worse (with some pleasant intermissions where I thought improvement was happening), and he's become an abusive father. And someone people shouldn't actually want to work with.

Barbara being Gordon's niece. I still cannot see any value to changing that relationship. At all. And then at one point, at least, it looked like he actually was her biological father. So he didn't just cheat on his pregnant wife, he also slept with his brother's wife/fiancee/girlfriend (can't quite remember what the relationship was). Well, that's admirable fellow, hmmm? And did his brother know? Did Jim? I think I have read the story, but so long ago, I don't remember details. Because if he let his brother think that was his child when it wasn't, then even worse.

Barbara as a protege of Bruce's. I like most of Dixon's Bat-family work (have not read his actual Batman), but do not like Batgirl Year One. I hated making her an idiot with the rope. I don't like Post-Crisis de-aging her (even more of an issue in Nu52). I hate the power imbalance where Batman and Robin knew her identity and she didn't know theirs. I liked old school where she was a peer rather than protege of Batman, learned on her own, and learned their identities when they learned hers (despite a brief memory erasure).

Dick cheating on Kori with Barbara. I hate the direction Dick took as a character, anyway (liked him much better earlier). But back-projecting it into the past was even worse. That was completely out of character for him to have done in that era.

Identity Crisis. I'm a big Ralph & Sue fan (well before they made him a joke and her derisive towards him). I hate bringing characters back only to make them evil or dead (hi Jean). I loathe retcons that make good guys more immoral (hi League). And it was used as justification of Bruce in Tower of Babel, which I also don't like.

Well, that's my starter list. What's yours?