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...where Izzy finally had to deal, once and for all, with her modeling background and put an end to being ribbed about it, when another resident (who actually liked her, ironically) had posted a bunch of photos of her on all of the locker doors.
The way Izzie dealt with that hazing might give the LW some ideas, but if not, then she could just relate that "particularly amusing" episode in that same group of people at an appropriate moment, and then turn to the ex and say, "So, what is it going to take to make you stop constantly trying to embarrass me in front of everyone?" That should stop her in her tracks.
It was a very gratifying episode for anyone who's been bullied or goaded. I especially liked Izzy's 'coup d'grace' line (paraphrasing here) "...and when you're all through with your education and struggling to pay off hundreds of thousands of dollars in loans... I won't have any debt." The LW's might be something similar... that when all is said and done, none of her hostility or insults are going to win the LW's boyfriend back, and instead are only likely to make her even more disagreeable to everyone else in the group. Or something like that.
Count me among those who also think the LW should say "No" to the carpooling. Saying yes does nothing to enhance one's reputation in this case, while saying no can only increase one's sense of self-respect.
It was an important moment when I finally realized that increasing one's self-confidence or -esteem is not necessarily a "feel-good" experience, but can actually be uncomfortable and feel unattractive. It's okay, though.