Gossip
Placing a heightened value on gossip is probably one of the most vain things one could do.
The joy of it though may actually make sense: I think it's probably the same joy that one gets when they feel intelligent, the idea that they may know something others don't and therefore feel superior.
However, it's still one of the most dumb joys that exist. Because unlike intelligence where it can be used for good, gossip is a hyperlocalised kind of intelligence that no one apart from that small intersection of people that know both you and the subject in question care about.
If talking about others - especially about how bad they are - brings you great pleasure...then how worthless of a person would you have to be, to focus so keenly on the minutiae of someone else just living their lives?