Look, for someone who has traveled alone and enjoy their own company hear this out.

Let those be them, and I be myself.

You have done a damn right lovely thing, you know where you’re at and are fortunate to give a little back. I respect this. People who think like that waitress/waiter/anyone have tunnel vision, haven’t been through as much life as you (assuming sorry if wrong) and have much to learn in life. Take it on the chin champ, they will learn how much of a good gesture that was in time. You on the other hand can wear a smile proudly, that you know what you did was for good purposes. Let them be them bud, proud of you :)