You have no control over what other people do or say, you can only control how you react.
Being able to not only understand this, but to be able to accept it is one of the big differences between lasting success and the occassional yo-yo'ing.

There will always be supportive people and there will always be unsupportive people, and yes, occassionally you will have be very direct (if not rude) to unsupportive people.

It's been my experience that most unsupportive people will actually change their tune when you're very direct with them (without being angry).* I think it's because they see you are quite serious.
Some don't however and you just have to be able to find a way to deal with them.*