If i Quit

Recent times, "have put my papers" have become fashion of the day..Hardly people stick for 2-3yrs in a company..I am an exception though..
I have seen many people with change in attitude in their notice period. Questions come in mind -"Do i really need to work", "Who cares"..etc etc..
Initially a question would be of the format "Yeah, i shall do it"..later it would change to, "The complexity is too high that i need to check the feasibility"..then at the fag end it would be"do i really need to do it?"..
Of course people are paid for the notice period. I personally feel, commitment should be the same throughout. But i also have some good friends, who have worked the same way, till their last working day!!. Hats off to them
Between , I am neither a manager nor a HR. I am just a engineer. Readers should not get these questions in their mind, so i am making myself clear here...
Hope i follow the same, when i get a chance to quit too.

Some courtesy plz..

On my way back to home from office, was waiting in the signal..It had started to drizzle by then..There was a public transport which had halted in the signal too. These days, we find some buses in chennai which ply with automatic door locking system,. Though they claim its automatic door, its controlled by the driver. The doors doesn’t have any intelligence of its own.
A old couple was knocking the bus door, driver took a notice and refused to open..I felt bit annoyed seeing it..By then it started raining very heavily..
First instant i felt, its wrong to board a bus in the signal. These days most of the signals are fitted with timers, we had couple of seconds for the signal to turn green.
They were repeatedly banging the door, and the driver turned deaf ears..Then the old couple staggered to walk and managed to reach the payment...What is he going to loose by letting them in?? Is he giving a place in his home for them to stay?? Is it too much of courtesy to expect from a third person??