When a person is having a rough day, or recieves bad news, and is stuck in a public venue without some way of releasing there emotions, leading to an explosion of anger against a complete stranger doing something minimal, or thoughts of doing so.
Dude at the fair I had such a case of stranger anger, Joe called me with the cast list, I was so pissed about the parts I wanted to punch the guy smoking in front of me.
Unfortunate Stranger: Where's the bathroom?
Guy: Are you serious?! The signs right there you dumbass, or can't you read!
Girl: Wow stranger anger much
Guy: Sorry I've had a really rough day.
(to the Stranger) Sorry sir.