One of great help
Many men many minds and one may recognize a problem of "NO" in the way different from the one we are talking about. In most cases, people say that they are not used but they help people who need their help and when it will be a high time those people will also help them. Though, it is rare happens like they say and they usually remain the only people of great help.
You think people need you if they always come and ask you for help? Sure, they need you, though it is not like they need you as they need their friends. It is like they need like they need someone who will do for free the whole stuff they hate to do. Or like someone. Who can spare their time and provide them with an opportunity to take their time.
See, it is not even a help those people need from you. When people ask someone for help they do it in the different way and they are grateful for help one provides them with. Though, when people as to do someone a one who cant say "NO" they at first ask it like a favor but with the lapse of time they just say what exactly you have to do, and that is it.
See, there is no help people are waiting from you, no help people are grateful for. It is like they tell their assistant what he or she has to do and they not even waiting for answer as they are sure that answer will be "YES". Thing will be clear if you ask yourself where those people are when you doing job for them.