Diversity. (I loved most fields just not enough to do any of them.)- I like doing ortho, procedures, medicine, gyn, peds (okay not really but still), trauma, cards, intubations, etc etc etc.
People- in general, people in em are pretty diverse. I also like dealing with consults.... I have friends in each field I interact with.
Undifferentiated patients- I like that no one knows what is going on.
Time off.
Money.