I fished some buddy tournaments with a friend of mine several years ago when I had one of those days, and not in the good way. We were fishing for smallmouth and both catching fish, but he was the only one catching keepers. Then about mid day he was the only one catching fish. It wasn't for lack of bites, I was getting plenty of bites on my shakyhead and hula grub, but I could not hook a fish to save my life! I had several casts in a row that my line would take off racing down the rocks and I wouldn't even get a piece of them on the hookset. I went so far as to change to an football head without a weed guard and continued to miss fish while he was culling. Of course there was always some good humored ribbing going on and it was getting pretty heavy on his end of the boat. He was telling me I was setting the hook on rocks so the next bite I got I told him to watch my line while I tightened up on it. The line was scooting down the bank and he even confirmed it was a fish before I set the hook and missed yet again. We traded rods, he caught fish on my bait and I continued missing fish on his. I'm sure by the end of the day it was just a huge mental block but I was baffled at how I could miss so many fish. At the time we both worked in the fishing department at Cabela's in KC, the next few days at work were pretty rough with all the jokes and trash talking going around
More often than not it works the other way around for me, but that was one of those days I got my hind end handed to me.