If I'm at a party, chances are I'm pissed off at whoever lied to me about where we were going.
Partying for me consists of everyone else presumably having a good time while I carefully pick a neutral spot on the where I can stare deeply and get engrossed in my own though, yet still give the external appearance of taking part as well. Every so often someone will acknowledge my existence by asking "Are you ok?" to which I reply by mumbling out some inaudible combination of fragmented words and sounds, while also wiping the long string of drool dangling from my bottom lip. After dealing with that periodic check-in, I've usually bought myself another 20+ minutes of undisrupted wall gazing time.