What minor injustices still live rent free in your head?

15 years ago I worked as a cashier at McDonald's.

If a customer wanted to change their order after you'd added it to the till, you needed to get a manager to remove the items. The total value of these removed items was reported when your till was being counted at the end of your shift - the term was "T-Reds". For example, your T-Reds for the day might've been £9 if two orders of £4.50 were cleared from your till.

For most cashiers, 90% of these T-Reds were due to customers changing their mind. The other 10% would've been due to cashiers making a mistake (or, in rare cases, cashiers trying to do something naughty).

If your T-Reds were over a certain amount (£10, maybe?) you were given a lecture and required to sign a "retraining slip" at the end of your shift - the gist of which was basically "I haven't done my job very well but you've now told me what to do better, thank you".

Some jobsworth manager with a big grin on their face telling me I didn't press the till buttons very well and me having to admit responsibility - all because a customer decided mid-order to get a large meal instead of a medium. Fuck off, you patronising cunt.

What's still got your goat?!