Have you hated a character at first?

Sasuke for sure. Shu from guilty crown always crying inori, but he managed to man up later.

One recent character I can think of is Yu Tosaki from Ajin. Like he's a right prick to begin with but then he becomes a pretty cool dude in the second season.

why yes yes i have http://www.cartoonbrew.com/wp-content/uploads/2014/02/steven-giantwoman-b.gif and then http://vignette2.wikia.nocookie.net/steven-universe/images/b/be/Crying_Pearl.gif https://68.media.tumblr.com/6503dae8288dc3a964357ac1194b028f/tumblr_inline_nl08kiC9si1rep7nh.gif http://68.media.tumblr.com/5e3d1235841e90973f85f621a7903dea/tumblr_inline_nmdtzqAvdE1qbl67k_500.png https://media.tenor.co/images/a490980b693d79b54372d50a82a99e31/tenor.gif https://media.giphy.com/media/lYZHAdgazzm5q/giphy.gif https://68.media.tumblr.com/1d7df8a35f4db7fadec14d873e345d62/tumblr_oaw98k7iJv1tandono2_400.gif https://media.tenor.co/images/5c6243b7ac67b5fc27bda3b257a446b1/tenor.gif https://68.media.tumblr.com/ba4e03787f23071cbd1262d50f587732/tumblr_inline_nlhu9k5zKm1qdo426.gif https://68.media.tumblr.com/13b225d554f3f63f180feac3a4fc9592/tumblr_oayqqvnAyZ1t13lago1_500.gif https://vignette2.wikia.nocookie.net/steven-universe/images/a/a5/Pearl_blushing.gif/revision/latest?cb=20160910050642 https://s-media-cache-ak0.pinimg.com/originals/0f/bc/c6/0fbcc67510d4af6e9ae00ac2d3a881f7.gif https://vignette1.wikia.nocookie.net/steven-universe/images/1/1e/Cry_for_Help_The_Horror.gif http://i.imgur.com/6N6pHfP.gif WE MUST PROTECT THE PEARL MADE OF PURE SALT

Only character I can think of is Mr Satan from Dragon Ball Z. Back when I was a wee lad watching the Cell and Buu sagas, I never understood why that character existed and why he was still around. https://i.ytimg.com/vi/7S_mlIYw9bI/hqdefault.jpg I mean he just looked so goofy and wasn't half as strong as the other main characters. Back then for me it was all about the fighting and screaming and "AAAA stop talking and throw lasers at each other already!". This character had none of those so I didn't have much patience for him. Of course over time that changed after I got older and started going back to those episodes and looking at things from a different lens. Now he's one of my favorites and have no problem saying this. http://images1.wikia.nocookie.net/__cb20130111210525/video-game-championship-wrestling/images/2/27/Real_Mr._Satan.png

Benten from Uchouten Kazoku Most the time she's a conceited $&@#%. I'm not sure why the other characters are so hung up on her. But every now and then she's almost likable. https://s-media-cache-ak0.pinimg.com/236x/a4/46/1b/a4461bf9e6ee25a4aad18fe0fcba3935.jpg

Any Gintama villain. They write the show that way :| twas too easy. Guess i'll go with a different show. I hated Dokuro-chan from Beating Angel Dokuro-chan, but eventually got over the sensely violence ~.~