Pluralizing abstract nouns

If a noun denotes an abstract concept, emotion or behavior, then, as a rule, it cannot be used in the plural.

Here are a few such nouns that refer to abstract concepts:

Realization
Self-interest
Forgiveness (and almost all words ending in -ness)
Running
Greed
Violence
Cooperation
Flowing (and many gerunds)
Intelligence
Information
Contempt
Disdain
Disgust
Admiration
Respect
Envy
Hunger
Comprehension
Stupidity
Pride 
Despair 
Acceptance
Humility
Suffering
Pathos
Pity
Arrogance


Many apparently abstract nouns, however, can be pluralized as long as they are being used with non-abstract intent. The trick is to recognize when they are being so used. Usually, an explicit or  implicit concrete noun (underlined below) will be present.

 
Love (but if referring to say, delightful little children, loves)
Hate (but if referring to things that one hates, then hates is possible  - my pet hates)
Beauty (but if referring to people or animals, beauties)
Reading (but if referring to lectures and conferences, readings)
Interest (but if referring to the things one is interested in, interests)
Hope (but if referring to  the objects of one's act of hoping, hopes and dreams)
Writing (but if referring to the text that has been written, writings)
Liberty (but if referring to unwarranted, lewd or presumptuous acts, liberties)
Delight (but if referring to the objects or the causes of delight, then delights)