In my sketchbooks a few little marks can remind me later of how a place smelled, felt, sounded (tasted, but I'm trying not to blog about food all the time) and how I REALLY thought it looked. A snap shot is just that - a SNAP shot. It just doesn't take long enough for me to engage all the senses.
Carrying a sketchbook around (and PAINTING in it) is such an enjoyable part of my life! It enriches everything. When your life influences your art, your art influences your life - or something like that.
Just paint - you don't even have to show anyone. But you'll probably want to.