Sarcasm is an adjusted stress reaction.

Huh. I just had a thought about Iroh's late son having been old enough, if he was serving in the army when he died. (Though I can't remember how long ago he died -- more than three years would rule him out.) And if her parents had designs on offering her to Ozai (either for himself or for his son and heir), that gives room for all sorts of upset when they discovered she had something going on with the wrong branch of the family... ETA: Also, now I'm wondering how long Ozai has been the Fire Lord and how long ago Iroh went from being heir apparent to passed-over general. Because while Iroh was the presumed next Fire Lord, his son would have been more likely for Mai's parents to have designs on marrying Mai off to, probably from her childhood. I can't remember the timing because I've only seen the series once, I'm afraid.