I have the good fortune to have been blessed with what I affectionately call "Brain Radio". Many people have it. Some people listen to covers all day. I like to play around with it and just listen to progressions and pull out the interesting bits. When something grabs me, I play it out on guitar and drums so I don't forget it.
Half the time, the 'original' stuff turns out to be a derivative of some popular song. For example, here's a progression
which I later recognized to be a derivative of an extremely popular song by The Knack.
I love playing out ideas on the ditto-pedal, as it allows me to build up a huge collection of song fragments for later use. I also like to be able to try out different rhythms and concepts on top of the loop, as it exercises both my playing and imagination. It sure beats a metronome.