As a former waitress the one thing I can add to this is that a tip is optional, customers do not have to leave a tip. That is their choice as well as how much they choose to tip.

Is it helpful to leave a tip , yes it is because that money is needed. And I was grateful for every dollar left as a tip. But I didn't expect it.

I sure as hell wouldn't argue with my bf about it after he spent time and money to make my day special. Things like this is what makes guys and girls stop doing nice things for you because it is not appreciated and there for stop doing it. then you wonder why they no longer put in the effort.

Did you look and see if a gratuity was already added to the bill? If so that was part of her tip, so the 10% your bf left gets added to that.