#1
When your playing just sucks, you can play at your best, you **** up much and so on?
#2
Everyone does. End of story.
Only play what you hear. If you don’t hear anything, don’t play anything.
-Chick Corea
#3
Yup, what food1010 is true.
Everyone has them.
Just don't play for one day and you'll be fine.
#4
^ Exactly. EVERYONE has a day where you think you're just terrible. Just set the guitar down and go drink beer or something.
#5
I believe that those periods where you are playing badly, or perceive your playing to be bad - let's call them rough patches - are the times when your playing is getting better.
Like going to the gym and training your legs - you need a period of recovery before being able to move heavier weights.

Not saying you need a break from playing necessarily but hopefully you see where I'm coming from.

We all get these periods too so don't worry about it.
Sometimes I'll either stop playing for the day and listen to some music/get out of the house/watch a movie etc.
Other times I'll completely change the style of music I was working on - if I'd been working on a single note solo for a few days and it starts to grind to a halt I'll go and find a chord melody/classical piece or similar.....