I've had a friend do this but with hair. My hair used to look like a rat's nest and it made me very self conscious and insecure. I told my friend I was considering putting more effort into styling it but she said that would be too much. That we're not the "type" of people to do that(aka we have better stuff to do). She always looked down on other girls for putting effort into looking good since she thought it was trivial.

We talked it out and later went shopoing together. It's been a couple months but she's much better now though, we both try to get each other to wear more exciting clothes now. She also complimented my haircut. This really is an insecurity on their part.