That's a toughie because, for the most part, I like someone or dislike someone and that doesn't change much. (Unless you're Ziva, in which case I hated your guts starting mid-season 6...though it's better now, and I like her again for the most part. So, it's back to where we once were. *g* And that doesn't count.)
Okay, ya know what, after thinking about this for a good long while, I figured out it's Tony.
*waits for people in the back to stop fainting*
See, thing is, I liked Tony just fine as a character when the show started, but he was just
too much. Too loud, too raunchy, too silly, too childish, too jock, too playboy, too everything. I remember thinking that he should just
dial it down.
And then, I don't really remember when, but I think it was during Frame Up, I suddenly saw the
real Tony. The guy behind the "too much" mask. And I repeatedly Gibbs-slapped myself for being too blind to see the obvious: that Tony is not who he tries to make people believe he is. (And he's damn good at it, too. He fooled me, after all! LOL!)
Once I realized who the character really is, I fell
hard for the boy. Loved him fiercely ever since. :)