So many people just make inane suggestions; if you don't like it, it must be the worst ever, right? For example, you Sims people-- there are MILLIONS of people who LOVE the sims. Just because you hate those people doesn't make the game the worst in history. Not your forte, im sure, but not the worst.
For example, I find killzone to be utterly generic. But I wouldn't ever say its the worst game EVER.
On the other hand, I'd argue that the game series defined by Cho Aniki would have to be the worst.