Being an American I am used to tipping. That being said with a $100 (3000 baht) bill I have left 1 cent, less than a baht as a tip.
I have mentioned at Makro that I tip, Usually cartmen comes to help me pack the truck.
But to pay a turd $15 an hour to ignore me, I refuse.
I have been paid less than $15 an hour while being shot at.