This might be at home in another part of the forum but I felt I needed to share this.
Player 1: Have backup arrived yet.
GM: Yes, you can hear the hum of the teleportarium.
There is a bright flash and you can feel reality ripple.
Player 2. Hey the backup where spacemarines where they,
GM. Yes, as per the agreement you made with the Lord inquisitor, If you needed backup he would send space marines.
Player 1: Do you have a picture?
GM: Err sure one sec. http://cghub.com/images/view/8159/
Player 2. I fall to my knees an praise the Emperor for the return of the primarchs.
GM: Aw hell. Wrong picture. **** it, lets roll with it.
Player 1. Wait what.
And there is how that game went to hell.