Well I just saw the best now lets have your worst. Please elaborate on your noms if possible! Now lets make this the "bomb-diggity"
(warning sarcasm ahead for potential fan boys)
Atari Jaguar- Seriously wtf am I looking at (is what I think when I first saw the controller). An ugly, uncomfortable, bulky controller with way too many buttons. But wait you can add on overlays to enhance your experience! Even if you wrap a dead bird with pop corn, its still a dead bird.
PS1- Got by with it at the time but the future Playstation gamepads make this one look archaic. Always hated the D-pad on this one myself, for this reason I enjoyed the N64 controller which had stick option.
Sega Genesis 3 button- I always hated how cheap this controller felt. Light weight, mine always had something rumbling around inside, short cord, and the connector never fit snugly in the controller port.