I've been doing a lot of hiking recently, and one thing I like to do is let my mind wander.  Usually when I'm walking or hiking or doing some activity that doesn't require brain power, I listen to music or podcasts, or I think about what I need to get done, or how to solve a problem I've been working on.  But lately I've been going out, leaving my electronics at home or in the car, and just letting my brain do what it wants.  It's kind of a cool sensation, almost like observing my brain in third person.  I can see an idea appear, and I just let my squishy computer go with it.  There's no objective or end state or anything I need to remember or write down.  It's just low-level mental processing, turning the gears and cranks, for no other reason than it's enjoyable. #psychology