Why???

Why do people hide stuff ? Why can't they just let the person know? Is it so difficult to admit certain things or are they scared? But scared of what? Losing the person, hurting the person, or scared of admitting?

Why is it that the one person you bank upon or trusts the most ends up doing things you hate the most??

I have no answers .. and I believe no one has. Even the person who hides , does not have the answer for this WHY......