When to leave??

[Bartman387]

A post over in the B&M forum made me think about this topic. I've heard numerous ways to tell when to leave, when you're ahead, when you're behind, etc, but these seem like bogus reasons. If you are ahead, why quit, something must be going right? Just because you are behind doesn't mean you're playing bad, could just be on the bad end of variance.

So what is the measuring stick that everyone uses for whe to leave? I personally follow H.A.L.T. and have found that if I leave a session unhappy with my play I was one of those four things.