The holy grail of writing is having readers who get lost in your story. When your beta readers forget to make comments, that’s a good thing. Really it is. Most writing advice is about how to achieve that wondrous state with great words and perfect sentences. They tell you things like – don’t use cliches or adverbs, they throw your readers out of the story. Be careful about the slang you use, modern slang will throw your readers if your story isn’t set in modern times.