All nouns in English are either countable or noncountable, and this affects how they are quantified and whether they can be made plural. Many abstract nouns, used to talk about ideas, are noncountable. This issue relates to subject-verb agreement, rules of article use, and the vocabulary used for quantifiers.
Using articles appropriately is one of the most difficult grammatical points in English to master. It is not necessarily essential in speech, but it’s something that should be checked for when writing.