I think that’s true in every field, and students don’t appreciate how much harder it is to provide meaningful constructive criticism. When I was a TA with tons of papers to grade, I’d spend tons of time on the papers on the top of the stack, killing myself to provide detailed, in-depth criticism in a sincere effort to help the students to improve. By the time I’d reach the bottom of the stack I would just skim the work and slap a grade on the paper. I’d feel so guilty about giving short shrift to those students, but they would be happy as pie while the students who had gotten all of my concerted attention would be livid about all of the red ink.