Being positive vs peaceful to manifest good health

I often hear well-meaning friends and relatives say "be positive", which doesn't resonate with me because I don't believe in faking it.  I recently came across this video where Deepak Chopra says:

@ 6:15

It's not that you have think positively all the time.  You have to get in touch with your emotions, you have to share them with somebody that you love, you have release them, you have to express them, because if you repress emotions that creates its own biology too.

@ 8:30

A peaceful mind is more important than a positive mind.  Because a positive mind can be working really hard at it, can be stressful to be positive all the time.  But when you're at peace, that's a wholly different thing because all the biochemistry of anxiety disappears.