It happens not only in games, but in mos aspects of our daily life. We just assume things before having any real experience with it. In case of games, it usually involves judging a game because of developers, that very few first screenshots or just because of the title. Many times games whose people where not expecting to be good turn out to be really great and games that had everything to be great turn out to be very bad.
Many times people already put a game in the 'not buying it' even before trying it out. Their prejudices and the fear of spending $60 at a game that may not be great many times make them miss great games. Other times it make us pay for a game who fail to live the hype.
I believe that being more careful and not judging a game before playing it is a better approach. This goes for everything in life. Food, people, experiences... It is always a good idea to give it a chance before passing any judgment. Don't base your opinions in second hand thoughts. Make your own. You may be surprised,
PS: Sorry about the low quality graphics. I am doing this one in my job and using some old pics. You may recognize some from previous comics. I promise a very new one tomorrow... afternoon... maybe.