The side that is west of the east side.
"West side is the best!" -- Ali G, West Staines Massive "East side is the best!" -- East Staines Massive "West side is the best!" -- Ali G, West Staines Massive "West side is the best!" -- East Staines Massive "East side is the best!, erm... damn! You iz tricked me." -- Ali G
Derived obviously from the Los Angeles street gang territory, a lot of Hamilton youth like to proudly align themselves with a gang that they have no idea of the politics on; now fallen into either general or comical use. "West side" refers to Hamilton West, "East side" refers to Hamilton East. You don't have to be a member of either of these.
Which reminds me, I went to a new school in Standard 4, and I remember a little 10 year old bogan coming up and asking me if I was a rapper or a 'mettler'. The concept that you could like music that wasn't rap or metal worried me.
CraigBox is a west-sider that has lived on the east-side for long enough to not really know who his homies are any more.