A real world example: I bought my PS3 (at launch) for the next iterations of Tekken, Gran Turismo and Final Fantasy. All of them were several years late. The biggest disappointment of them all was Gran Turismo 5. And the main reason was the track loading times. It took almost a full minute to load tracks, and almost the same to load back menus after the track. I just got bored really fast, and didn't play the game for more than a few months. I seriously even considered buying a SSD drive for the game to my PS3 (many GT5 players did). Long loading times (more than 20 seconds) are a definite show stopper for me. I definitely wouldn't even consider buying GT6 if it had 500% longer (5 minute) loading screens before & after every track. I am a married man now, and I don't have infinitely much time to play games (especially if the playing is basically waiting for loading).I absolutely do not mind increased load times even if they were 500% longer than currently if it means we'll finally have some real advances in texture quality, texture variety, asset quality, asset variety, etc. in games.
Our players (Trials Evolution) are complaining (in our forums) about the 15 second loading screen every time you change to a different DLC game world. Our level loading times are 3-5 second long (we stream pretty much everything all the time). That keeps the players happy and gives them less opportunities to think about other things they might want to do instead of keep playing