I feel very strongly that one should learn from one's mistakes and weaknesses (if any) in the papers or essays submitted. As such, I do point out some serious errors that students make, and sometimes I require them to make the necessary corrections in order to improve their work and, at the same time, to learn from the mistakes or errors that they make. Not to mention, sometimes this may improve their grade too.
However, comments on the students' mistakes and errors may not go down well at times. Sometimes, the request to rework on the papers may be frowned upon. I had one student remarked to me when I pointed out the shortcomings with the request for reworking on the paper: "I don't have time to look into it. I just want to get this out of the way."
When I heard such comments, I felt very sad, disappointed, and to a certain extent, upset. It was not because of the fact that my efforts went unappreciated. But I sometimes wonder what went wrong. Was there too much work for the students? Was I being too demanding? Or, what else could this be?
Whatever it might be, that was a sad day for me indeed.