This week entering lab, I was exhausted to say the least. I guess I'm the type of person that visually looks tired, or at least unhappy, when I'm exhausted. Here's how Andrew reacted to the more glum version of me.
Me: "Hi Andrew"
(pauses to look at lab notebook)
Andrew: "you look upset"
Me: "no just tired"
Andrew: "try not to fall asleep in my lab"
Me: "oh you haven't noticed, that's my goal every week"