That's what the nuclear stress test turned out to be. I wouldn't have dreaded it nearly as much if I'd known that I would get to be the one to say when I'd been on the treadmill long enough. I don't get a lot of physical exercise, so I was fairly fearful at the idea of staying on a treadmill, its speed and slope steadily increasing, until some Nurse Ratchet-type told me I could stop. In fact, I had created an entire slideshow of mental images of myself lying face down, arms and legs tangled around various posts, while the still moving treadmill scraped against the side of my face.
It wasn't a bit like that. And my knees didn't hurt at all during the test! And the nurses were nice, too!
Now I'm feeling good. Good enough that tonight I'm going to a birthday party, at which I'll completely replenish my supply of positive energy from abundant sources of love, laughter, and Mexican food.