In my line of work, dirty diapers are nothing. It seems like everybody has one "smell" or body fluid that gets them. Truthfully, I can't stand vomit -- that bitter, sweet, warm smell. . . .(told you I shouldn't play).
Also nice is when you find an old sippy cup under the couch and open it, only to find that it's probably been there for a couple of weeks. Rotten milk = nasty.