I'm fairly opinionated on the whole tattoos/piercings concept while never often voicing my thoughts on it.
As far as piercings go, any piercing other than the ear bothers me in a way. My sister got her belly-button pierced and I was a little shocked/disgruntled, but I'm fine now. For the most part, belly-button piercings aren't too awful, but I dislike anything in an obscure part of the body.
Tattoos are another story however. I'm often bothered by even the smallest of tattoos, but again, I rarely ever say anything about it. Whenever I see a tattoo I think to myself "what will that look like when (s)he's 60 years old...?" I know it's a fairly contemptuous standpoint, but it's also a somewhat realistic one. I've asked a friend of mine who wants to get a tattoo that same question and he didn't seem to care about it, so perhaps that's the general consensus.
I can't help it, but I form opinions about people with tattoos or piercings which I usually regret.