I remember getting this ultimatum by my first college boyfriend's female friend, which led me to buy my first matching bra & underwear set, in black, with lace. Too bad I hadn't been fitted properly, because the experience caused me to believe that underwires were the WORST (they are, when they're not your size!).
Speaking of which, if you look at Hazel and think "Oh, I'm her size!" you are probably NOT a B cup. Jamie either did a bad job measuring her, or wacky cartoon physics are at work here. Go get yourself fitted!