<prompt> Human: Not sure if this is the right sub or not, but since it involves spending habits it seems appropriate. Ive always tipped on pre-tax subtotals on bills when appropriate to tip dining out, for instance. Over the past few years many bills have included 15, 18, 20, or 25 suggestions on the bottom of the bill to provide an amount for someone to quickly write in that amount. Lately Ive been noticing however that the suggested amounts at the bottom are computed using the final total with tax. Ive always been told to tip on the subtotal before tax. Is this a relatively new thing to suggest tip amounts on top of the tax? Is this just the way new software systems are set up for the POS registers?  <response>: That suggestion at the bottom is for people too stupid to calculate the tip for themselves. The extra by adding tax is a stupidity tax. 