So..I liked the question. What game did you buy because it got good reviews and you thought you'd love it...and were disappointed?
Mine was Spore. I was so psyched to get that game. I really liked it for a bit, but I haven't played it in 2 weeks now...not a good sign for my newest game. It was just...tedious in the later stages.
One thing that really didn't help with choosing that game was the overwhelming number of reviews on places like amazon that had nothing to do with gameplay, but were rants about DRM. It kinda made me tune out some of the stuff I did hear.