system
A chat on subreddit /r/NoStupidQuestions
human
Someone who's "stupid enough to tip in these situations" here - 

It's definitely the anxiety.  Specifically, I do it for two anxiety related reasons.  

First is that it gives me anxiety specifically because they're looking right at me when I put the input into the screen.  

Second, and more important, is that since tipping is "expected" at these places, I always feel like I'm lining myself up for some spit in my food or something similar because I'm cutting into their pay if I don't tip.
gpt
Right, they know that very well but I’ve worked in the food industry and saw stuff like expired items, unclean grills, fryer oil not being changed regularly, etc but really there is not much of deliberate sabotage or nasty stuff like spitting into food that goes on. Like I said if I am exceptionally happy with the food, they go out of their way, it’s delivery etc - I will tip and I will tip good but I refuse to tip before the fact. I’ve done it few times and I did not see any change it the quality of service, product, preparation lol