Cons to look out for

I've been hit by both of these in one week - one local, one not.

The nonlocal one: a highway farm stand selling pomegranates that were moldy inside. After buying several - which looked lovely - I asked if the proprietor had a knife handy, to cut one open; she said no and advised that I'd end up with pomegranate juice all over the car. As it transpired, I would have ended up with mold all over it instead.

And, in beautiful downtown Brunswick Basin, in a store that'd been doing a brisk business for hours, I handed over a $20 bill to pay for my small purchase, saying "here's a twenty"; Cashier#1 handed me the change, then did a double-take looking at her drawer, and said "wait, you didn't give me a twenty, there's no twenty here - you must have given me a five" - and took $15 back. I'd seen it as a twenty when I'd taken it from my wallet, so stood there looking dubious. Cashier#2 looked over at the drawer, and assured me Cashier#1 was correct - "no, there really isn't a twenty in there".
I made a (G-rated) expression of unhappiness, at 110% volume, still standing there - and lo, Cashier#1 discovered it had been a twenty after all, that she had placed under the drawer; presumably with all the other twenties.

So... trust, but verify.