I was given that lesson when I was walking through Venice , years ago. I was walking with a friend, and I was taking pictures right and left. My friend said " Stop taking pictures with your phone, and take some with your mind. " We stopped and just looked around us ( St Mark's Square, not too crowded, a busking band playing, an artist painting on his easel , people wandering and laughing). I can picture that scene so easily after several years - more so than I ever could have done if I'd snapped a picture !