When I have a day like that these days, I tend to not bother playing, different if you're playing live of course, then you have to bluff it
I guess that it proves that you can play perfectly technically but if the feeling isn't there it just sounds sort of lacking. I've played guitar, (6 string) since I was about 8, obsessed with it in fact. I went through a thing around about the age of 50 when I couldn't pick up a guitar, I developed a real aversion to playing guitar altogether. 10 years on and I'm starting to play 6 & 12 string again and really enjoying it.
I was still playing bass for my sons band during part of this time and took up the pedal steel, which I've been attempting to learn seriously for about the last 3 years. In a way it's been a blessing taking up the pedal steel, it's made me re-think how I approach 6 string guitar and I'm finding it exciting to play again.
So I guess I had a stumble decade on 6 string guitar.