I worked for about three hours as a barman.

When I was about twenty I did a trial shift as a barman during the day when the bar was fairly quiet. There was a guy at the bar who ordered drinks and every time he ordered exactly the same drink he would give me less than what the drink cost. This happened four or five times and got me bloody frustrated, so the last time it happened I leaned in close to him and said something like "mate, you know how much your drinks cost so how about you stop being a dick and give me the right fucking money".

I then got a tap on the shoulder and the manager said he didn't think I had the right demeanor for the job, I swear I was set up and the guy drinking was a regular who was fucking me around at the managers instruction, testing the young pup to see if he could keep his cool. Clever bloody bastards.