Here's a funny one:
A number of years ago (won't say how many) I was working on an album (won't say which) for a very famous female singer (won't say who). The session consisted of very long, hard days, and there were a lot of odd, story-worthy happenings. But one in particular will never leave me...
This particular singer wanted to be VERY involved with EVERY tiny aspect of the recordings, and indeed that was the artist's right, I would say. On one particular day, there was a well known session guitarist (won't say the name) who had come to play. This very good player had his whole setup there, and was playing in the control room, seated, with his very large pedal board on the floor in front of him. He had switched on the wah-wah pedal, not to vary it for the wah effect, but to use a static position for a particular tone. The artist wasn't satisfied (never was) with the tone, so she actually jumped over in front of him, and began turning the knobs on his guitar, as he was playing and recording. Of course, this is not done with session players (if with any player)! But the guitarist soldiered on, not wanting to create any bad vibes...he just wanted to get the session over with! As he played, she kept turning anything she could find on the guitar (even the volume knobs). Finally, she began to tire a bit, so she knelt on the floor, and leaned her elbow on his right knee. This created pressure downwards, and threatened to change the tone of the wah pedal by the movement. This went on for quite a while, the artist turning knobs looking for "the" tone, and the guitarist trying with all his might to counteract the force of her weight on his knee, and hold the tone! She started yelling over the music that the tone seemed to be changing in the wrong way...he continued to try to hold tight. Finally, he couldn't take it anymore, and just screamed out, YOU'RE PUSHING ON MY LEG DAMMIT, AND CHANGING YOU ARE CHANGING THE WAH WAH PEDAL TONE! THAT'S WHY THE TONE IS CHANGING! He actually jumped up, and ran from the room. The artist was merely frightened, not understanding. They finally made up, though she never understood what had happened, and somehow the overdub was completed...
It was just one of only 105 guitar tracks which were kept on that particular song!