It's impossible to overstate the importance of staying playful on your instrument. If you aren't willing to explore, and possibly look like a fool, then you are closed off to so many possibilities and discoveries.
I've been fortunate enough to play with numerous musicians who exemplify that daring mindset, and who have pushed me to pursue it in my own playing, wether in a group or by myself. It's made me a junky for the thrill of discovery. I especially love when it happens to a group of musicians and you can feel the electric current of inspiration flash through the room.
It's with that adventurous and open spirit that I make it a point to pick up the guitar and just explore. It keeps it fresh and exciting for me.