In early high school, my dad told me three ways to tell if I was at a good party:
1. Windows are throbbing from the music being too loud.
2. There is at least one dog running through the house.
3. There are people passed out on the woodpile.
Sadly, by the time I started going to parties that would end in splinters in the face, woodpiles were out of vogue. (Even growing up in Oregon). It's taken me years to come up with a list of possible modern equivalents for number three. My list so far is: dining room (or basement) dance party, at least one of your friends thinking they are in a different building than reality (i.e. convincing self you are in a cottage as opposed to a tiny apartment), noise complaints from up or down neighbor (passive aggressive notes get double points), or peeing outside due to no hope for using the bathroom.
I may need to expand the number of the modern list. But I do know that every time I see a dog at a party, I pet him in between his ears and think, "I'm at a good party."