Book excerpt: Football isn't all about players, tactics or even satellite telly. It's about a culture. A culture born out of the obsession, fanaticism and humour that is football fandom. The ultimate product of that culture is the Geezer. The sexist, elitist and abusive yob who, clad in his designer clothes, follows his chosen team week in, week out. Every club has them in their hundreds, but who or what are they? And just why do they do what they do?