I was checking some bits at the bank following a withdrawal and a well dressed business man in a sharp suit about to leave the branch. The local security guard, a smiling chap who always recognises me opened the door for him and was rewarded with a THB 100 note, pressed discreetly into his hand.
I had no idea you tipped bank staff nowadays but this guy was well happy and I got an even bigger smile as I left the building. But I didn't tip. 😇