I think because the fans make heroes here of anyone who performs well it's easy for fairly ordinary players to start getting ahead of themselves. The "Ryan Taylor over the wall" chants for example. At most big clubs his presence on the pitch wouldn't be tolerated yet here we're singing songs about him. Nolan came from Bolton reserves and after scoring a few goals was demanding a 5 year contract. Easy to get above yourself in this atmosphere.
Nolan was a fixture in Bolton's first team for the best part of six or seven years.
The comment about Ryan Taylor is daft as well. Most people acknowledge that he's shite, but he's given us a moment of brilliance that really matters to look back upon.