I know that a variant of this question has been asked before, and recalled what my Creative writing teacher told me about when to use capitalization after a colon, by using the following three example sentences for colon usage.
In a complete sentence, the capital case is optional. 1. This is what I think of cats: They steal your breath.
In the following two examples, the capitalization is not optional to change, therefore the words after the colon must remain lowercase.
This is what I think of cats: nothing.
This is what I think of cats: scary, tiresome, snooty.
In other words, do the above examples properly illustrate proper colon and capitalization usage for American English, regardless of essay style, and usage for non-essay papers?