The Monty Hater (okay, that doesn't exactly narrow it down). He has occupied the same seat several rows behind me for a decade now. Oldish bloke with a very distinctive nasal whine; he would never say anything at all either in support or against United other than to criticise Monty, week after week after week after week. For example, if a substitution was made and it wasn't Monty he'd go, "Haven't you got a number 4?" Every week.
More than once someone has finally flipped and turned on him, a memorable time being when one guy turned round and yelled, "Always fucking Monty! They're all fucking shit, not just Monty!"
One week I lost it too; can't remember exactly what it was I shouted but it was something along the lines, "I've been listening to you for five years now; either lighten up or fuck off somewhere else!"
When Monty left he was a bit quiet for a while but soon switched his ire towards George Long. However, he was never able to summon up the same passion or frequency as he did for Monty. This season I haven't heard a peep from him; in fact on Saturday I'll have to check to make sure he is still there.