The other day at Lotus' I made a purchase for 181 baht and paid with a 1000. Because my change was going to be 819 baht and not divide evenly into bills I tried to give the girl and extra baht coin so I would get back 820, all paper no coins.
Well the girl refused. I tried to explain to her why I wanted this but she continued to refuse so I gave up. After I got my change back I told her , look at all these coins this isn't what I didn't want. Of course she just gave me the blank stare Thais use when they "play dead" to avoid confrontation.
To be fair this is the first time this ever happened. I told my landlord about this later and asked what was up and she just said it was a village girl and it's to be expected.