Positivities and Negativities: Just a matter of perspective

When seeing a filled glass, some people say that the glass is half empty, some people say that the glass is half full. But even though it's half filled or half empty the glass is actually filled !
Says who that pessimistic people cannot be optimistic ? and vice versa ?
Says who that negative events can only give negative effect? and vice versa too?

below I will give you a story that can prove my rhetorical question above. Maybe the story is quite strange and the grammar would be a shipwreck, but I hope you guys will understand the point that I want to tell you....

Here Goes NotHing !!~~~

A little bird is flying to the south during a cold winter. The sheer coldness of the winter have caused it to froze and fall to an open field. While the bird cannot move its wings and body, a cow is coming near it and poo on the bird. Under that cow dung, the bird started to feel the warmth of it and is rejuvenated from its freezing condition! The bird feels very happy and chirping joyfully. A passing cat heard that tweet and decided to check what it is. Following the harmonious sound, the cat found the bird under the cow dung, and agilely the cat flick the bird from the poo and eat it.

from this story we can actually see that even a sick thing like a dung can actually give a positive effect - even saving a life. Conversely, a happy and positive thing such as a joyfull tweet can lead us into unpleasant condition....

So there you go!! Behind every negativities lies positivities, vice versa !!