Why would any ghost want to hang out in a graveyard?

Of course it's easier to meet other ghosts in a graveyard. It is their equivalent of the local pub. A place to meet up and swap stories of their life (and death), exchange haunting tips, and post flyers warning of exorcist visits or advertising day/night trips to the nearest castle for mass haunts. And yes, if they stay too long, they get a bit drunk and start showing off their 'orbs'.