I have never had my blood drawn, but I am sure if I did it would make me pretty sick by looking at it being drawn. I would probably have to look away the whole time. I have nothing against blood, but I think if I saw that much coming out of my body I would not be happy.
I dislike shots, but when I do have to get them, and it has been forever since I last got a shot, I don't really care. Sure, they pinch a little bit, for about a second, but overall they are not that bad.
In short, getting my blood drawn would probably bother me more than getting a shot.