1. O'Brien. Yes I can't stand him at all. There's just something about him that made me groan with frustration every time it was an O'Brien centric episode
3. Vic Fontaine. (Glad to see I'm not the only one that disliked him)
4. Mirror Universe Kira (and regular Kira too, but she wasn't as bad as her alternate persona)
5. Zek. Love the actor that played him, just couldn't get past how cartoonish he was.