In a previous job when I did internal tech support our company used the remote control feature of Microsoft SMS to assist users who were completely lost. One day I started a remote session to a user's pc, and I found that wherever I clicked, context menus popped up. A few seconds later I realized what was happening.

"Are you left handed?", I asked the user over the phone.

"Oh my God, how did you know??", responded the lady.

She must have thought that I could see her as well as control her computer. The awe and disbelief in her voice was enough for me to have to mute my phone while I had a good laugh.