I had never thought of this before until someone mentioned it, but, does it bother you when people use a 'couple photo' as their profile picture? For instance, a boyfriend/girlfriend duo that posts a picture of the two of them for the photo?
The argument I heard was that everyone has their own, for example, Facebook account, so why would you use a picture of two people when it's your own profile. Similar to your driver's license, it's a picture of just you, not you and your husband, etc.
Personally, this does not bother me, I think it's sweet and the person is who owns the profile is still in the picture and you can clearly distinguish who is who. On the other hand, I do find it kind of strange when someone uses their baby or child's photo as their PP; that clearly isn't you and you likely have an entire album, or six, dedicated to your child (I know I would, who's with me!?) so why not use your own face for the main picture?
This is a weird topic but how do you feel about it?