we have a small grocery store down in our office building and every time i buy something the owner keeps on giving me a gum as a change even if i don't want to.i noticed nearly all his items are priced w/ 50 dirhams.the idea of giving back the gum came to mind but instead told him im going to get my 50 the next time i visit his store,the next day we get even.we do this every time and now he remembers not only my name but as the guy who doesn't need a gum.