When you're walking through town with your headphones pumping, you're shut off from any outside distractions - allowing you to get deeper and deeper in thought.
This could spark a killer idea if you're subconsciously thinking about a project, or it could just go off a weird but entertaining tangent.
Sir John Hegarty once explained to me (I was at a talk and book signing session) that you shouldn't walk anywhere while listening to music. His reason was that you may miss things. Everyday things. Things that could be used in a script. Things that are so real, unless you witnessed it, you'd struggle to think of it.
I'm not saying he's wrong - each to their own. But I do disagree with him somewhat.
I recently walked by a couple in their mid-20s at a bus stop. The man was clearly upset and the woman was trying to comfort him. I had headphones in.
So it got me thinking about what the situation could be. And the possibilities are endless. It kept me thinking the whole way to work - and at random intervals since (it's probably the inspiration for this post).
Now, if I wasn't wearing headphones I may have caught a critical piece of information, that would've revealed the story - or at least hinted heavily towards it. And, that would've been the end of that. Nothing left to ponder.
Even though Hegarty has a good argument, I'm not going to change my habits. I like getting lost in the depths of my mind while listening to tunes, so what if it isn't always productive?

