Phone calls non-stop
Say, here you are doing your job and than one comes to you and asks you to do some job he or he has no time to do. Sure, it is necessary to be friendly to people and help them, treat people just the way you want them to treat you. According to such a policy you will say "YES" for sure and do a job people ask you to do.
It is okay to help those people who need your help. Though, make sure that one really needs your help and he or she really has no time or an opportunity to do that job him- or herself. Think over, is it really help they need or they just want to avoid the necessity to do their job. In case they trick you, they will be back with their request again and again and again.
Thing will get worse with the lapse of time and people will get use that there is one who can do the entire job they don't want to do. Soon, you will have your business phone-calls at home. People will call you asking for your help and will still be too shy to say "NO" and you will neglect the rest you want to have in a favor of interest of other people.
Do you need those calls at home when you want to have a rest or to have fun with your friends or family? Don't you have your own jib to do? Isn't it enough duties for you at home? Sure, you have a lot of things to do at home and you have no time to do a job for other people, let them know it.