I can usually get past misplaced or improper punctuation when I'm reading, so long as the writer's meaning is clear. My current pet peeve is writers don't know how to write things like "could have" as a conjunction; I keep seeing things like:
... could of ...
... should of ...
... would of ...
Drives me freakin' nuts! I'm seeing this more and more often in published, ostensibly edited, works.