The Adviser has this habit of strolling past all the bays in the lab when he first comes in each morning saying "Good morning!" without pausing his steps. Which usually meant that when I look up in response to the voice there's no one there. 

This, repeated now over a period of years, occasionally makes me feel like that I'm being greeted by an disembodied voice or, as the lab's alternative hypothesis goes, that our PI has somehow learned how to apparate.