Special laziness tax

I was in the restaurant in work today at lunchtime and decided to have a small bowl of fruit.

I'm picky about the fruit I want in my fruit salad so you might see me carefully selecting grapes, melon, apple, orange and peach. You won't see me putting kiwi fruit or anything exotic like that in my bowl.

So, I carefully picked my fruit and put it piece by piece in the elegant styrofoam bowls provided. You see we have a pay by weight system in operation so the bowl needs to be light I suppose.

I brought the bowl to the checkout and put it on the scales. The person working the register keyed in the code for fruit and the display rang up €1.16.

I put my hand in my pocket and took out the coins I had in there. I had a €2, 2 x €1 and some small copper coins.

The person serving me then says "€1.20".

A number of thoughts flashed through my mind, the dominant one being that the person serving me couldn't be bothered to count out change for €1.16 so the cost was rounded up to €1.20.

I could be speculative about the person's arithmetic capabilities but since it's possible to key the amount in to the cash register I'm left with no option but to assume that this is pure and utter laziness.

Part of me is beating the other part up saying "You fool. You should have refused to pay". Then the sane and rational part of my brain invokes two popular theories.
1. The law of diminishing returns
This means that incremental effort yields progressively less benefit. In other words, beyond a certain optimal point the more you put into something the less benefit you get. I have tried, I really have, with this restaurant. Now I think I've passed the optimal point. There would be a whole lot of comment and energy from me and nothing meaningful coming back my way.

2. The equity theory
This means that if I get my way and get to pay the actual charge for my fruit, somehow the situation will re-balance by me being deliberately overcharged for something else. Or worse, someone will hock in my food. Think about it. You work some place and some customer comes in being a real moron. What do the urban myths say happens in the kitchen with a steak that has been returned? Oh yeah. It's hock central in there behind those swinging doors.

I welcome verification from anyone who say spent the earlier part of this year working in a restaurant.. do they really hock on the food of serial complainers?

Bad stuff.