How about a WORST 10 cards? I.e. cards that when they show up, make you yell "TRUCE" to your computer, only to have your roommate look at you like you're crazy.
My top 10 worst (1 is worst, 10 is 10th worst):
1. Possession -- makes any game screwy
2. King's Court -- changes the dynamic of the game more so than any other card, to the point where it's annoying
3. Swindler -- often screws up any strategy, and luck dependent
4. Cultist -- it's almost always quickly sought after early by both players, forcing double-Silver openers, which is boring
5. Urchin / Mercenary -- often whoever gets the first Merc wins
6. Tournament -- a cool card, but like Merc, whoever gets first crack at the Prizes almost always wins. lame.
7. Tribute -- can't count on it for nothin
8. Saboteur -- see Tribute
9. Transmute -- because, duh
10. Scout -- what's a top 10 worst list without Scout?