Ah, you gotta love random distracting comments.
I was playing doubles in a national club league match with the head pro at my club a couple of weeks ago. In the middle of the second set (in a tight match) at 15-15 on my partner's serve, as he was picking up a ball from the back fence, one of the other pros starts asking him about the whole schedule for junior groups this autumn.
My partner just about flipped out and ripped this lady's head off. After all, she'd been teaching a lesson for an hour already, so she could quite clearly see we were in a tight match. It's not as if she'd just walked up to the courts.
We must keep striving to find new depths of idiocy.