Refusing to comply with the clearance=paperwork. There are a growing number of pilots that see speed instructions as optional. Last year I had Irish low cost traffic depart on a SID with a 250kt speed limit. Accelerated straight up to 300kt. I queried it and he told me on the frequency that he "couldn't be bothered with it". Righto, paperwork filed, radar and r/t replays sent to the airline.