What is the meaning of Useful ?

I think that some people really ask for it when they call others useless but they are actually useful in ways but you do not or may know what they may be good at . I do not like this kind of people and if you are trying to choose a team member for your group , you would of course choose someone who is good in that subject or topic and do not call the other person useless as he may be good in other topics . I know that this may seem meaningless to you now, but when you work in the society , you would have to go through this kind of problems . Hope you people will understand what I mean but if you would not listen to the advice you may suffer in the future . Haha I just wrote what I think of this topic . Just an advice , take it if you want to .