I know that it is irrational, but I have this fear that if I refuse to tip when paying for food in advance (fast food, or food carts, etc), that it might be ref

I know that it is irrational, but I have this fear that if I refuse to tip when paying for food in advance (fast food, or food carts, etc), that it might be reflected in the quality or quantity of food in my meal. So I pay the damn tip.