I've had it happen, and more often then not its always someone with a silver lid.
I no longer tolerate it though. I was raised to respect my elders and for years would just quietly stand there and stew.
No longer though. I'm not retired, I work and have appointments to meet. You cut me off now and the whole line is going to hear about it. Sorry, but you have all the time in the world to meet your coffee people at Timmies.
You get what you give and as far as I'm concerned you treat me with disrespect and that gives me full allowance to do the same