In Supernatural season 1 episode 10 "Asylum" we see an asylum haunted by the spirits of those who'd be inhumanly treated/experimented upon there.
The civilian couple that got mixed up in the action get separated for a bit. The guy sees a spirit and assumes it's his girlfriend. The spirit then proceeds to walk up and kiss him. He kisses her back for a few seconds and then realizes it's not his girlfriend but rather a creepy looking spirit, and runs off.
We later learn that the spirits are actually
not trying to hurt them, they're trying to whisper a room # in their ears to lead the Winchesters to the evil doctor who experimented on them.
But that still doesn't explain why the spirit would just initiate kissing a stranger. Do we know why?