Baseball:
Tim Redding (waved his hand in "don't bother me" fashion when I asked for his cracked bat, then gave it to someone else when he left the field).
Matt Stairs: (Lied to me about a bat being cracked and then gave it to another fan after coonfirming that it was).
Jason Giambi: (Nothing to do with 'roids..he promised me a cap (c. 2000) when I gave him a matted Mickey Mantle 2 pg. magazine ad, then ignored me afterwards).

Football: Any of the IDIOTS (Burress, Pac Man, Vick, etc.) who have engaged in criminal behavior.

Basketball: Same as football, plus Lebron James (based on a cheap shot he took at former President George W. Bush in a 2009 interview).

Dave M.
Chicago area