What are stupid things that pilots do that bug you?

[upintheair_]

If ATC doesn't answer it usually means they are "on the other line" with another controller.

As a pilot, the thing I find most annoying is pilots who switch to the freq and instantly transmit without taking a few seconds to see whats going on. That and pilots who call ATC when they have just given another AC and instruction and need a readback.

No you don't understand what I mean. I'm taking about a radio frequency with a conversation going back and forth. Large long pauses between transmissions make it hard to know when you can make your call. Are they done? Are they not? I'm not talking about terminal or centre. I know if they don't answer they are usually on another line.