Maybe That Hideous Reflection Is Mine

Quoting Staind in "Outside":

But I'm on the outside
I'm looking in
I can see through you
See your true colors
'Cause inside you're ugly
You're ugly like me
I can see through you
See to the real you (Full lyrics)

Slipknot -in their aggressive way- clearly state it in "I Am Hated":

Now I'm not pretty and I'm not cool
But I'm fat and I'm ugly and proud - so fuck you (Full lyrics)

Finally, Marilyn Manson seems to have a word on the subject, in his song "The Nobodies":

Yesterday I was dirty
Wanted to be pretty
I know now that I'm forever dirt (Full lyrics)