Neither of the two really bother me.

The worst for doctors would have to of been shots. But since I was in 6th grade and in the hospital for double pneumonia, the nurses kept on missing my vein because I was so dehydrated. So many times that they missed it, that it just stopped bothering me.

But if I had to choose between the two, it'd have to be dentists just because of the sensations. I can't stand the sound of the scraper against my teeth, or gagging because of accidently putting a tool too far down my throat, making my gag reflex kick in. But I have to say, the worst part was sensation of and hearing the crunch of my teeth being pulled when I needed braces.