Obviously Ruben Patterson, that goes without saying. But that's because we know he's scum of the earth. On the court, if I knew nothing of his character, I might've liked him as a player. So I'm going to pick players by how I disliked them as basketball players (because, for all I know, there's a player who's a secret serial killer in his private life).
So: Telfair, Kenny Anderson, Damon Stoudamire, Shawn Kemp (because trading for him was what broke the Whitsitt era) and, I guess, Detlef Schrempf, because I loved him as a player when he wasn't on the Blazers and he just sulked the whole time because we traded for Pippen immediately after acquiring him.