
Why do manager treat employees like a college students ?
Whenver I leave early from office when ibhave no work at all, my manager usually ask to inform everytime . Does that necessary?
I mean if we are completing the task on time, why shlukd we waste our hours of time sitting idle in office .
What do you think ?

I had the same exp when i was starting my career. I once told my manager, i finished the work for the day so i was leaving. His response was i should find some work and try to do it. One must learn to go beyond their normal duties. The worst part was this is the line of discussion they take up during appraisal and decide on the bonus. Salary is for regular work. Bonus is for the extra that we do.
From that day onwards till date, i never finished any work before time. Something that can be done in 30 mins, i always took 3hrs. Anything that can be delayed, was delayed.

Talk to him about it and let's see what he says.