When you are home on a friday night with absolutely nothing to do. You usually feel friday night-less when a group of friends is having a small party or gathering and you're not invited/told/notified until the gathering is actually happening.
In summary, being friday night-less sucks. It makes you feel like a loser. This is how I feel right now.
(the day after the gathering)
Person who was at the party, "Hey, why weren't you at the party?"
Person who was not... "Well that bitch of a friend didn't invite me."
Person who was atthe party, "Oh... So you were friday night-less?"
Person who was not... "No duh, shithead.