I do this when asked for my ticket in public transport. I'll wait until they are in front of me. When they walk away before I am ready, I put my ticket back so that they have to come back and wait until I am ready. I think, public transport should be free and financed only by taxes. I may have helped people who just forgot to get a ticket or need to catch the train quickly and still waiting for the app to validate their ticket.

Only for longer trips accross the country I prepare my ticket in advance. I can't explain it.