When I was only months into the job, straight out of uni, I was working with a very scary and imposing partner who was about 60.
He was washing is hands in the loo one day when I came in for a wee. As I stood at the urinal, he finished washing his hands and came over and demanded to know what had happened on an earlier telephone call I was on.
I was immediately struck with stage fright and just stood there with member in hand, completely unable to pee.
After about a minute he just blurted out, genuinely confused, "what are you doing???"
"I'm trying to go to the toilet"
"You're not trying very hard"
then he just turned on his heels and left