A painting built upon a faulty foundation will not withstand the test of time anymore than a building will.
I set the timer for ten minutes. Thirty minutes passed. The values are beginning to work. the colors of the background are working but the shadow colors must change while maintaining their value. The line where the table top meets the background on the left is totally off. Regardless of the colors and the values working, if the perspective is that far off, moving on without correcting the drawing would be a mistake.
Having cleaned my palette and brushes, I used my finger to smudge the line where the two planes meet. I bit more correction is necessary in the next stage.
Forcing myself to work quickly, attempting to do ten minutes studies (even when I ignore the alarm) is a great way to start the day.