In one of my university math courses the professor was too nice. He gave the class one test, but after the students did not do all that well, he declared that there will be no more tests in the course, and all evaluation will be through a series of biweekly assignments, plus one big take-home exam assignment at the end. Then it gradually became apparent that the assignments had no real deadlines, as anyone who missed the official deadline was exhorted to still hand them in, apparently with no time limit at all.
Pretty soon the class realised the modus operandi, and we started to fall behind on the assignments. After all, other courses had strict deadlines for assignments and tough exams, so it seemed rational to focus on them and leave the course taught by the nice professor until later.
In the end, the only deadline which the professor could not avoid imposing was the final day the university required the marks for the course to be handed in. And so, as one would naturally expect, many of the students, myself included, ended up working through a pile of old assignments and the take-home exam assignment in a few frantic days at the very end of the semester, after the last exam in their other courses.
In the end my grade for the course was pretty good, partly because the professor was too nice to grade us harshly. But the absence of timely evaluation meant the students had little motivation to learn the material at a reasonable pace, and so most students did not get much out of that course.
It’s hard to say what could have been done about this at the time. The deterioration in the course was gradual, and it only became really apparent towards the end, when it was too late to do anything about it. I am guessing that the root of the problem was the professor’s apparent discomfort with giving any critical feedback to students.
After this experience, I have enforced strict deadlines for assignments in all the courses I ever taught. And I have never complained about strict deadlines in any other courses I have taken.