You know you play too much DoomRL when you...
...feel insecure visiting a theatre/stadium and not having a flak jacket, a shotgun and a few scraps of bandage. Or, if it's a big stadium, a nuke and steroid pills.
...see red dots, red dots everywhere ! Aaaargh !
...feel excited when you visit big cemetaries.
...can't carry colorful sweets, you must consume'em right away. And you feel impure doing so.