Some might be intelligent enough to headbutt you. It reminds me of what happened to me and three friends the other week-end. We were walking back home as two big guys and a small nervous one crossed our path. They wanted to fight, we calmed the things down, but the angry little fucker wanted to fight. He was like a kid that's bullied everyday but that is all hot when he's got his friends along to protect him... Everything was fine, finally, everyone went his own way without knees broken or teeth stuck in the asphalt.