Well am sick of making that dog solider's joke that I do, when ever I see this sort of thread.
So I'll give a serious answer.
Injections, wait scratch that, anything sharp, that includes needles, knifes or pins.
Basically anything that can draw blood, "keep it away from me".
Edit: Oh wait scariest momment, well I've came close to drowning, (five times.)
Trust me it ain't nice and most people who have expericed it will tell you, that drowning (Am refering to people who survied the experiance.) Is a terryfying event to go through, as a matter of fact I actually thought, I was done for the fifth time it happened.