You could legitimately argue that Metacritic and Rotten Tomatoes are biased because fans of a movie are more likely to go and rate it on the internet than people who thought it was a mediocre movie.
Uh huh, because people who LIKE things are more likely to take the time to talk about how much they like it than people who hate something? Wow, what alien culture is this?
Seriously though, those sites don't only publish user review scores (whom everyone knows to take with a grain of salt.) If both the critic review score and the user review score is high, chances are something is good. It's not that it sucks, the fact is you, the individual, don't like it.
In any case, that was a real conversation I had with someone over the internet. I asked him if he didn't believe the combined average of reviews, then what would he believe in, and he answered, "himself". In other words, the determining factor in whether something sucks is his own opinion. That's when I stopped talking to him.
Strife: I'm talking more about people who do this "~~~~Granterofwishes1223*!*~". I don't capitalize my username because I prefer it being flat when you look at it. Having the U stand out is a bit akward in terms of asthetics, don't you think? It's like a flat rolling countryside with a giant 12"toilet sticking out. Besides, I said more than 2 numbers.