As a medical student, a lot of my time is spent on waiting for my supervisor.
Picture the scene:
I'm waiting outside my supervisors office at 12:00. I've just rushed from teaching so I'm mildly out of breath. I'm ringing at the telephone on the front door to let him know I'm here so I can be let in. After many calls and no answer, I decide to see if he's on the ward.
I politely remind him that we had a meeting scheduled. He tells me to wait (which is understandable as he is currently doing the ward round)... but whilst I'm waiting, would I mind making him a cup of tea