I learned that people don't use the same words we technical folks do, so if you get a support call and ask "Have you installed anything?" the answer they give is no, but, if you ask "do you have any new programs or stuff", the answer will be yes.
Why? - My theory is that they either didn't know what "installing" was (nobody opened up the computer to put something in), or they themselves didn't do it.
You have to have a very strong ability to route around the person on the other end of the phones preconceptions of the world and get the right answers anyway.
If you're going to be an ISP, you're going to be on call 24/7/365, and you're going to see weird shit. More than once we had to deal with people wanting to post adult content for money.... and this was back in the days of dialup. Who knows what the heck the folks are doing today.