“One may understand the cosmos but never the ego; that understanding of the self is more distant than any star.” G.K. Chesterton

The harm caused by negativity contaminates the environment we exist in.

An emotion that does harm to the body also affects the people we come into contact with, and indirectly, through them a chain reaction can take place, that is capable of contaminating countless others we will never meet. In fact we are either a life giving factor in all of our social systems or a life taking factor. Energy and hope are either building up in the relationships we are a part of, or entropy is taking place – the winding down of life and hope giving collective energy.

There is a generic term for all negative emotions: ‘unhappiness!’

I have seen whole corporate cultures become destabilized, ‘unhappy’ and therefore unproductive when infected by negative and destructive emotions. Sadly, because the ego is driven by a need to look good and be right, these situations are difficult to turn around without significant attitudes of humility in key opinion formers. If this doesn’t happen because the opinions formed are ego driven, those involved will tend to blame everything except their own blindness for the situation. Scape-goating will never bring resolution.
But what about positive emotions?

Do positive emotions have the opposite effect on the physical body?

They do indeed, but we need to differentiate between short term positive emotions that are ego centred and ego generated, and the deeper emotions that emanate from our natural state of connectedness with our spirit.
The ego is always looking for happiness in all the wrong places. Happiness for the ego comes when happenings are going the way the ego wants them to go.
In contrast, our spirit always wants to lead us to joy. Joy comes through our spirit harmonising with and finding its place in the divine narrative that is continually unfolding. It is an experience that has a unique quality.