Less people = a higher concentration of douchebags (NZ)
More people = a lower concentration of douchebags (Anywhere that has a higher population, party central?)
Also,
I'm guessing when you were partying, you were associating with a few drugs, so getting high, wacked and/or itchy. And when you got back home and sobered up you only just started to noticed the douchebags again, pure coincidence.
Remedy - Keep partying hard I suppose..