Only the wisest of the wise understands that the greatest truth and wisdom is often ignorance...fo r most people are ignorant and we have to live with them. That is sad but it is the truth.
But knowing the truth allows you to react to it. Not knowing the truth would not even give you that chance. The sad part is when knowing the truth and knowing you can't do a thing about it. It is then that bothers you.
The buddha has this to say:
Do not worry.
If you can change it, change it.
If you can't change it, no point in worrying.
Therefore, there is no reason to worry.
Easily said but hard to do.