Now I can't cheer...
Apparently,
HIP! HIP! HURRAH! - Hip, we're told, derives from the initials of the Latin words 'Hiersolyms est perdita,' 'Jerusalem is destroyed.' German knights, not a very bright bunch, were supposed to have known this and shouted 'hip, hip!' When they hunted Jews in the persecutions of the Middle Ages. 'Hurrah!' by the same strained imagining, is said to be a corruption of the Slavonic word for Paradise (hu-raj). Therefore, if you ever shout 'hip! hip! hurrah!' You are supposedly shouting: 'Jerusalem is destroyed (the infidels are destroyed) and we are on the road to Paradise!'
I don't know if this is real or not, but hey, the phrase is now ruined.
Well, I can't remember when I have ever said this. Basically it's the priciple of the matter