The truth is that more than half of a person's life does not usually go as we wish.
Those who tries so hard to appear positive are usually those who feel totally not secured deep down in their hearts.
This is just like that those who put on real efforts to show people how rich they are are usually not the real rich people. Or their wealth and social status are usually neither stable nor recognized.
These weird behaviors all come from a defensive mechanism that roots in humans' intuition. This mechanism is called denial.
When feeling threatened by something, most people's first action would be to deny the existence of the threats.
It's like when you lack some ability but can't bear to admit that you lack it, the most efficient solution you can come up with would be to deny the righteousness of this ability without any reason.
This is totally not healthy.
It's harmful to let any single emotion dominate one's mind for too long, even if it's a positive emotion.
What you truly need is the diversity of emotions.
We need those positive emotions, because they drive us forward when we need to.
But we also need to have the liberty to express those negative emotions, because they are part of who we are. They are our natural needs.
Suppressing them by force would only push us farther away on the way of alienation and eventually turn us into monsters which even we ourselves cannot recognize.
But sadly, the blue side of life has been usually buried too deep.