Tattoos can work well if you've put some decent thought into them; something that somewhat reflects on you as a person but also has a story to back it up, or something or someone who helped change you (hence why you get all the 'Mother heart' tattoos), I would go with a small bar of Fight Club soap.
For piercings, that's more or a fashion thing, something to really show to the world (granted if it's on your face); small ones (e.g. buds) show a non-showy character, large ones give the almost attention-seeker or even the one who does isn't fussed about it all. After all, "Self Improvement is Maturbation, now Self Destruction...".
Anyway, those are my thoughts from what I've seen in friends and strangers, I'm fine either way, but the ones that do get me are the Huge ear-stretching plugs; they just seem a bit 'primitive-tribe'/ 'jeapordising-future-career-plan' to me, but again, could be a whole bohemian thing to another eye. "One man's trash is another man's treasure" (or my preferrence: "One man's terrorist is another man's Freedom-Fighter")