I was knitting with a friend once, and she kept complaining about how many knots there were in her yarn. So, I asked her to let me see the next knot.
As it turned out, it was just her yarn getting tangled with itself, making a twisted spot occasionally. (It was a single ply yarn, which tends to do that.) So, I showed her how to let the project dangle and unwind.
She stopped complaining after that, when she realized that it wasn't actual knots in the yarn.
I thought that was so funny!