A Norse Troll, A Mailman and A Banana Walk Into a Post

I was back at the credit union today. I had the same teller I had last time when the credit union was robbed. She told me that the robber had turned himself in because his picture was everywhere. The teller speculated that perhaps he had offended someone that would have been glad to dime him out (if that argot means turn him in, and if argot means gangster slang). That seemed likely since he was the kind of guy that would rob a credit union; he'd probably annoy other people too. I mean, I thought he was a jerk, and I never even saw him.
In a way, though, don't you feel sort of sorry for stupid criminals. At work the other day, two people came up to tell me about different criminals that were captured because they made simple obvious mistakes. Tip: don't give your cell phone number to the clerk and ask her to call you when the manager comes in to open the safe.
During the first story, I was kind of vaguely wondering why I was carrying mail in my hand, that had no relation at all to where I was headed in the post office. That's exactly the momentary inattention that would doom a criminal that, for instance, flashed a banana instead of a gun, but I was able to carry off with panache. Wait, does panache mean miming slapping your forehead with a broad gesture and spinning around to go back to your case? No? Never mind then.
Miming actually is the name of a Norse troll, although the record doesn't show that he ever slapped his forehead.