Random venting that is completely odiotic and unreasonable

So i work in the restaurant industry and I have to comp tabs everyday. If someone doesnt like their food, we will offer something else and take care of that person's meal. If we have an order that takes a little longer than normal, we might offer a free dessert. If something major goes wrong we would take care of the entire table. So basically how we handle it is proportional to the issue. Well, I ordered something online at chipotle and came early to pick it up. I figured it wouldnt be ready and it wasn't. I wasn't upset, chipotle takes no time to make. They hand me my order and tell me it's on the house, but in my opinion (because of my background) it wasn't necessary. I told them I wanted to pay, i felt wrong taking free food for no reason. They refused to let me pay and I asked again, probably should have let it go but again I felt morally wrong for taking it. Anyone else work in the industry feel this way? Now i actually am an unhappy customer because they refused my request to pay. I have encountered people that refused when I offered to comp their food and there are some people that you have to let pay. Certain people feel wrong about accepting free food and a business should comply with their request. Anyway, i don't know why but the situation really upset me.