I took up rock climbing in November 1999, in Yosemite Valley. I was 44. Old enough to know better. You'd think.
A friend, Mike, taught me the basics—in particular, how to tie in (attach the rope to my harness, using a follow-through figure-eight knot). Then he headed for the top of the short route—which I've always thought was Jump for Joy (put up in 1967 by Yvon Chouinard), but I now see that that's a 5.9. And I don't believe Mike would have started me on a 5.9—which isn't super hard, but it's not exactly easy either, especially for a greenhorn. But the guidebook description of an "initial bowl/depression" sounds right. Hmm. I never realized I had such an auspicious start!
In any case, what I wanted to relate is that after he disappeared and eventually the rope came snaking down the rock, how to tie in completely flew out of my head! All I could do was stand there and stare at the end of the rope. Then at my harness. Then at the rope.
Fortunately, right around the corner, a trio of dudely young men were getting set to start their own climb. I tiptoed over and asked, "Um? Would you mind showing me how to tie in?"
Of course, if they'd been responsible young men, they would have told me no. But nah, they were climber dirtbags and very happy to show me.
After that, I never forgot again.
Here I am reaching the top of my first multipitch climb, After Six (5.7)—a climb that, along with its neighbor, After Seven (5.8), I've since led. But that first time, following on the rope, was plenty thrilling enough.