Sometimes things can go wrong and you realize that drawing is bad and you have spoiled the page. For me the best way to deal with the frustration is to cover moleskine page with layer of gesso, leave it to dry and make an oil painting on top of it to finally sweep my disaster under the rug of daily routine without tearing the page out from the sketchbook.
This was a meditation on the film still from the Nolan's "Dunkirk" - movie incredible in many ways. I was contemplating this outstanding story of converting seemingly inevitable defeat to the foundation of the future victory.
Sometimes I paint even in smallest sketchbooks as well