A yid is an annoying, short-arsed git, and they generally walk around with their chest puffed out and speaking in an irritating form of the English accent. They usually barrack for shit English soccer teams.
They may occasionally go on local soccer forums, telling people to stop bitching about flares at soccer games, when they're only about 5'2" themselves... This (among many other things) often causes people to wonder why THEY of all people would bring up terms like "bitch" in the first place....
(When people see a yid, this common discussion usually ensues...)
Gooner: Hey, look over there, lads... a yid!
Danish: Yiddo bastard...