When you're in a patient's bathroom at the end of your shift, emptying the graduated cylinder of its contents, it's a really, really bad idea to exclaim,
"OH, MY GOD!"
even if you glanced in the mirror and got a good look at your end-of-night-shift, slept-on-wet hair, which resembles a coiffure Medusa would envy.
You're likely to hear panicked shouts of "What? WHAT?" coming from both your patient and her sister, and only if you're really lucky will you get laughter in response to your meek, "Oh, sorry. It's just my hair..."