Kevin James, the “King of Queens” guy, used to do a great stand-up bit about the fast-talking number-leavers. He’d also go on about the rhythm of a phone number - da da da… da da da da, and how certain strange people will divide the numbers the wrong way when they speak them. Funny stuff.
Here’s another pet peeve: People who call from another area code, but forget to give you their area code when they leave their number (usually older people who seem to forget that people who live in the same metropolitan area don’t all have the same area code anymore). You’d think that the assumption would be that if they don’t tell you the area code, that it’s the same, but I’ve learned to always ask. Also, I’ve run into quite a few people who recite the number, then the area code. You don’t write it that way, so why would you say it that way?