Heads Up Hit and Run a Problem?

[evagaba]

I played my first heads up cash games at both 50NL and 100NL on UB. At both levels my opponent got lucky against me, won about a half a buy-in and left a couple hands later. I played 4 opponents and only ONE stayed for a significant amount of time. The other 3 won lucky pots and left shortly thereafter.

I was wondering is this standard for heads up dealing with hit and run artists? Or did I just run into 3 uncool opponents?