Yes, its individual, but we are actually a lot more alike than people like to think. I never said to use it as a sure-fire way to tell how good a game is, but better games do tend to get better scores. Use it as a general guide or suggestion, not as your sole determiner. Its just as ridiculous to say that review scores mean nothing as it is to say they mean everything.
They do mean nothing for me, if I was to buy games based on scores, I wouldn't be a gamer anymore, as I dislike so huge number of games with high scores, it's ridiculous!
Better games tend to get better scores, but only if your taste for games is about what would be average of mainstream gaming community (and it is average for reason that more people play those games, not necessary like them a lot), if any of your finger is dipped into niche gaming, it's all over for you. You only get to know what's good or bad by playing yourself and metacritic annoys instead of helping to choose.