1) You pick up the mess when your team mate screws up near you (penalty).
2) Balls fly at your face, but you cant run away.
3) Dun wear the correct gear, and you are likely to end up with a sprained hand in a serious match.
4) If you are unlucky, boots make contact with you instead of the ball.
5) If you are really unlucky, the ball will make contact with yours. =.=