My co-worker needs to show some professionalism.
Is your coworker not doing what he is supposed to do at work?
He hasn't done his work on time and I'm pissed off.
It is good to work while you are at work. You should be able to expect coworkers to do their jobs when they are on the clock.
Who do you think you are to judge my work ethic? I'll write a fifty page chapter on work ethic and shove it in your face.
You can help me with a school essay if you're planning to do that.