Is It Bad To Leave Work On Time?

This has been crossing my mind ever since the day I started working...


Should I stay back and help the others as they are so busy and there's a long queue of customers but its the time to go home??


I won't get paid for the 1st half an hour for staying back....


But you know, I felt kinda guilty for not staying back to help them a little while as they were quite "kelam kabut" serving customers...


Now, I felt that I'm not gonna be popular among them.... Sigh....


Should I be more selfish and go on home without turning my head, or should I be selfless and stay back just for the sake of friendship...