I remember once playing a 1v1 match online in COD4. The other guy convinced me not to shoot at him immediately, then lead me to a spot on the map where we could boost each other outside the map and walk on the skybox. 10/10.
I have friends from COD4 days I still talk to, but sadly can't game with due to time constraints. I would say I have kept in better touch with these group of friends versus the friends I made in real life since then.