Students are the most ungrateful creatures on earth

I teach in a college I gave retest for students who got less in CIA so they can score better in endsem. 75 % attendance is minimum. I'm not supposed to tamper with attendance. But those who were in the border of 69 and 75. I manipulated so they can get the hall ticket.

And this sem I don't teach them. When they see me in college. They don't even acknowledge me. Not even a smile or a good morning. That's all we expect from students. Only a wish or greeting and that they can't give.