Just recall this incidence.
Once went to a fast food outlet just to please my little son over his good performance in his school work. The banner outside the fast food outlet printed: XXXplate--RM4.99; YYYplate RM8.99 and so on. O.K. then. Placed my order, got my food, paid over the counter and shocked to discover that my change was short of 2 sen. On enquiry to the cashier, I was told:"no more 1-sen coin".
"What a nonsense! Your banner outside the shop states ".99 " for all sorts of food sold. Furthermore there is a bank just NEXT to the shop and it is still open. THIS IS CHEATING! I would like to see your manager." You can imagine how furious I was!
After get to know the whole truth, without any apology, the manager told the cashier:"give him 5 sen."
"Look here, Mr. manager. I am asking for my 2 sen." He just kept quiet.
You know what!? I gave 3 sen back to the cashier as a change. See, it's a matter of principle.