Earrings, hair dying and regrowth, tattoos, the wearing of shorts, women wearing pants, etc.=vanity
Now, I don't know about anyone else, but I'm vain enough without all that stuff.
If we wanted to go beyond the explanation of vanity to specific injunctions against such things, we could. But the problem is that, no matter what they are told, many people will continue to do what they want and find ways to justify it. It is sad. To me, it's a sign of spiritual disorder--all to varying degrees, of course, but it's still there. And we all have some kind of spiritual disorder, but we should be aware of this and appealing to the Physician for help in putting it to order.
I have a hard enough time dealing with my own vanity to deal with other people's, but excess body modification can be very distracting. People should realize that everything they do has an effect on others--even our secret sins.