I recently finished grading my very first batch of assignments as a teaching assistant. Previously I had worked as a special kind of "general help" teaching assistant that wasn't assigned to any particular course, so I didn't needed to mark anything before this semester.
Most students fared rather well on their first attempt at understanding functional programming using Scheme. In fact, I only gave one failure, though it was clear this person either forgot to do the assignment until 30 seconds before it was due, or simply planned to drop the course soon anyway. A grand 1% is what they earned. By and large, the class did a good job.
But they could have done better if only they had read the questions more carefully!
Everybody forget something. Maybe it was the substitution model they were supposed to show for their multiply procedure. Or maybe they missed the fact that they were supposed to program in an iterative style. Perhaps they ignored the fact that 25% of the grade was specifically allotted for testing and documentation.
This kind of thing is common, but I never realized how many students it affected until I marked all of their work.
Ah well -- my many comments will hopefully serve as a reminder to be more careful in the next few assignments, and if nothing else, I now know myself to reread my own assignments a few times more before rushing to answer!