Some characters have a physical characteristic that makes them inherently more visible. These include the height of the Danger Brothers and John Revolta's white suit, as well as the unique character models of Brimsworth Buckswaggle III, Generalissimo Ritzini, and Alsphone "Snaps" Mcgee
In new art, this could include the height of people like Disney or Sikh, the extra details of, say, General's Medals or Hair's Hair, or just Wheel's Wheelchair, or Olive. Just about every character has some sort of natural highlight, and since everyone stands out, nobody stands out.