I hate %, give me a option to round up to the nearest 5. This is useful for my financial tracking, and I'm willing to bet a lot of people would like nice round numbers. If I buy a coffee or whatever and it's $7 I round up to $10, not because I'm trying to give a good tip but because it's more convenient for me when I'm sitting there doing my finances (I track everything) and while I know that not everyone would universally agree maybe they would only want to round up to the nearest whole dollar the fact remains I feel like most places would actually end up with more total tips overall if that was a one button option