My main gripe is still with those who refuse to sing. The majority of our chants are family friendly, so that's no excuse for parents etc. If you're going to a football match, at least make an effort. And for those who won't sing because of nerves, just take my approach and get absolutely slaughtered before kickoff.
It's only natural that people will leave because of a lack of success, people only have a limited amount of patience, so i'll give some of those a benefit of the doubt, not everyone is into mentally torturing themselves over a football team.