The first one I see simply has a clock behind the client so looking at it is not different from looking at the client. That is what I mean by being good at it - not that they don't look at clocks, but that they arrange it so it is not glaringly obvious. I watch the time myself so for me- it is not a big deal. In my own office at the university I have two clocks - one behind the students and one they(or both of us) can see. Often they do not even notice the clock behind them and give me (completely undue) credit for knowing timing stuff. They would get twitchy if I looked at the clock that they can see, but have no adverse response to me looking at the one behind them.