Look it has happenned many times... To which, I note exactly what I order, remember the prices, factor in tip and tax and I asked if it is enough. If there is a dispute, I tell them what I order and why I think I am paying my fair share. There will be times where I will be generous and put in extra bucks. Other times, I don't like it when I have to put in more.
Example of anger, I order Chinese food with a group of people (about 7 people). I only order Scallion Pancakes which should cost 3.25 according to the menu. I put in 5 for tax and tip. Well, the money was about 5 dollars short and I had to put in the 5. I did but I made sure I told EVERYONE, I am NOT paying 10 dollars for a 3.25 (not including tax and tip) dish. They finally figured out that the entire group forgot about tax and tip and shorted about 1-2 dollars each.
