They argued with my 87 year old mother when she said she didn't have a computer that she did.
I also like to keep them online if I have time. I keep interrupting their written script to see how many times I can get them to start over before they hang up. I never tell them on a Mac not a Windows machine.
The best is my son, he owns his own IT business and they called him on a slow day. He knows what should happen when they tell him to do something so he rattled the keys and would tell him what they were expecting him to do but with slight changes. When they didn't get what they expected they would get confused and have him do something else. Said he kept them online for 30 minutes.