I used to build foundations and frame hotels for this guy who didn't get other bids after the first one, but still beat me down in price every time. I bid to make 20% profit. After a couple of buildings I realized that he beat me down by exactly 7% each time. So I began adding an additional 10% and thereafter made 23%, when everything worked out, and we were both happy. Just an unrelated memory that I can relay here because I can.