I know this has been said, and said better by others, but it is worth repeating.
In my opinion, validation is everything. And I am not exaggerating.

People need to feel listened to and reassured that their feelings are their own- they are neither right or wrong. The need for acceptance and belonging are the basis for healing. Validation helps get the "walls" down right away; it is much easier for a person to hear and accept help when they can tell that they are not being judged.