When you overreact, you're not just making a big deal, you're making a BIG DEAL.
Overreacting is like playing the trombone in a library - it's just too loud.
Underreacting: the opposite of overreacting, but not really. Underestimating the importance of a good sandwich: a tale of woe and disappointment. Dramatizing: because you're still not overreacting, but you're getting closer.