I've spent a lot of time and energy wondering how to deal with obnoxious people and their nosey, insulting comments.
The key is you don't. Don't play the game at all. Those comments are nothing but their attempt to bait you into a losing insult match. They've played it before, they get their friends involved. They get you all riled up and bounce you around like a hacky sack. Once they're done, they drop you and move onto the next person.
While you're thinking of ways to create an FU attitude or quick comebacks, they're out laughing and having a great time with friends, not thinking about you in the slightest.
Btw, trying to create the FU attitude is just another version of letting them win. Altering your behavior to defend yourself against theirs.
You have to see their game for what it is. Its nothing but a game for their bored, small minds, realize that it is not personal , and recognize that they target you because you are easy to manipulate and they can always count on getting a good emotional response from you.
You can say that I'm making it sound too easy or I don't know what I'm talking about but it's really that simple.