One thing that really annoys me is people who stick their non-spitcap fitted headset mike into their mouths before transmitting.
It sounds horrible and are obvious to anyone but themselves. It also wastes a lot of airtime when the controller (or even his fellow pilot!) has to ask for confirmation.
What is wrong with placing the boom mike in such a position so that you canīt hear your own "S", "T" and other classical mic sounds?