Thanks for reading my article, @katarinamiliv, I'm glad you like my thoughts and observations! : ]
I agree with your addition; I think that one of the most common ways negativity can serve us and our environment is boosting our motivation and determination to succeed in something useful.
Yea, or for example - what Freud names 'sublimation' - using some negative tendencies in a positive way, useful for us and the society. Like a person with aggressive tendencies who becomes a surgeon, so he saves people's lives while actually immersing into his negativity somehow. :)
Wow, the surgeon example is quite interesting!
I guess that the same applies for police officers and many other occupations.
yes :)