Yes it is! Unnecessary use of the speedbrake and I throw a tantrum! Waving a rolled-up newspaper around and shouting 'you're wasting my fuel! Have you ever REALLY been short of fuel in your miserable short existence?' sort of question. Far too many young pilots use speedbrake almost every flight- it's almost a dummy for them, and they'll use it happily knowing that they will probably have to fly level later, but such is their horror of being high they overuse it badly. 200 up to MCT is an ATC requirement- it is using it when planning and foresight would have prevented it that annoys me. I used to fly 747s. The potential to really waste a large amount of fuel through poor planning instilled discipline!
Colsie- good luck with your eventual entry into aviation. You have a very good understanding from your question. Airbus needs you! Work hard.