there's nothing wrong with them. generally it's a sociological thing where people feel inferior, feel that they must be unique, that they must exact the idea of grotesqueness from the Victorian era (whether they realize it or not)
quite honestly, i could ask you why you thought the mullet was a good choice.. ease up on how people wish to present themselves. chances are, they have more honor and dignity than almost anyone else from day to day. it's through this form of 'self mutilation' as you quaintly put it below that they, myself included, express themselves. not through materialism, but through body art. and yes, it is art because are is subjective whether you see it as such or not. for all you know, someone who looks like this is quite possibly a great philanthropist, scholar, philosopher, or a scientific genius that will change the world far beyond anything you or myself could ever hope achieve.
in addition, the level of prejudice you managed to convey in your original post rivals that of many religious closed-minded people i have encountered thus far in life. i'm sorry you can not look past certain peoples appearances. perhaps you should self examine at a later date.
I really like the plugs in the last picture.
For further info, the female with the many 'bumps' on her back seems to have sat through a play piercing session. That is non-permanent and usually non-scarring piercing done for photography, short term decoration, or occasionally for masochistic reasons. Play piercing is also showcased in the photograph of a male with many piercing rings down his arms and leg, and the photograph of the male with a corset-like design on his throat.