You know why critics exist? So they could tell you what THEY liked about something whatever it was game, movie or book. Indeed, review is reflection of one's opinion on certain subject and thanks to those reviews we can see how OTHERS have liked something. If critics have liked something, then it probably has some redeeming qualities and is worth looking into even though it may not be my cup of tea. Like I probably wouldn't like romance movie even if it had good reviews simply because I have no interest on that genre what so ever, but I can still see if it is well made and would fans of that genre like it.
Also if critics haven't liked something then it may be because it was not their thing or it was just badly made. Also I am pretty sure that if some critic says that some movie, game etc was bad then you should look at other reviews and see if they liked it.
The reason of reviews is to give us direction what ever we should buy something or not and WHY we should do so.
And yes I always do research on games and movies I buy a lot. I see all the trailers, look gameplay and read even some spoilers to see if plot is any good. But the reviews help me to decide what ever I buy or not. BECAUSE, there are a lot of games and movies with cool trailers and stuff but then thing itself can be quite horrible (Walking Dead Survival Instinct or Avatar: Last Air Bender MOVIE)
And I don't let any reviews decide if I should buy something or not. They give me direction and hints.
They are not bad, they don't "dictate" what I buy or think is good.
Like take any movie with extremely bad reviews and it is most likely really bad if you have watched any other movies of same genre and have something to compare to. Lets take "House of blood" as an example. I haven't seen any good reviews for it. I watched it. It was pretty horrible.
Even "horrible" movie can have some good things about it, but you still should get hint that there are better ones to spend your time to.