what would make you head-butt someone?

the zidane head-butt on materazzi that rocked the world cup was all over the news for a while after it happened. they had to go to fifa hearings and pay fines, but neither of them ever told exactly what was said. there was all kinds of speculation. it was reported that materazzi said everything from insulting zidane's mother/sister, to accusing him of being a terrorist. professional lip readers were brought in and the men were asked repeatedly. and now, just when you thought you'd just have to go through life not knowing what was said, it has come out. materazzi finally tells us what he said. apparently, while pulling on zidane's shirt, zidane said something like, 'if you want my shirt so bad i'll give it to you afterwards'. and materazzi said, 'i'd prefer your sister'. now, i don't have a sister, so i can't really say what i'd do in the same situation, but i'm assuming i woudln't head-butt someone. i've had people make comments like that about my brother and i've never hit anyone for it. and especially in a situation like that, you know it's not a serious thing. he's obviously just trying to get you worked up. zidane has been playing the game long enough to know that. but whatever. now we know what was said. we can all finally sleep soundly.