My bugbear is bus ticket inspectors. They keep barking demands for my photocard at me (bear in mind I'm deaf so this takes a while until I've figured out who they are and what they're saying).
I don't have a photocard. Then they get right arsy and start wanting my details and making unintelligible threats.
After about 6 times of this I now know to point out that yes, my Oystercard has a Disabled Railcard loaded onto it, and if they were trained properly, they would know that a Disabled Railcard has no photo, so no, I do not have a photocard, and do not appreciated being threatened with court etc for having a perfectly valid ticket.
I'm still furious with the guy when I was a student, who made me pay for another ticket because the ticket office had sold me a single to London instead of a day return - which cost exactly the same amount!
On the plus side, when our family had to get train home after car broke down in a rural area (all the insurance counts for nothing if there are no locksmiths within 100 miles), a lovely ticket bloke clocked my hearing aids, confirmed they were from the NHS, and insisted on giving us the 1/3 off we'd have had with my railcard on the grounds I was clearly entitled to it.
I used to commute to Cricklewood which at the time was ungated. Once they had a few inspectors - the first half dozen people off the rush hour train beat them up and everyone else went past. Not an easy job.