Any difference between "don't forget it" and "don’t you forget it!"?

Question

Sometimes it gets confusing whether we should include "you" when we want to tell someone not to do something.

For insantance, normally if we want someone not to do something, we would say "Do not do it". But it is quite often that I often see sentences like "Do not you do it". That makes me confused.

For instance look at this sentence: "I’m the boss around here, and don’t you forget it!"

What would change if the speaker did not include "you", such as "I’m the boss around here, and don’t forget it!"

So, my question is basically, is there any difference between; - "Don't do it!" - "Don't you do it!"

Regards,

Answer 1

"Don't you ..." (as a command, not a question) is a frozen expression that reflects the grammar of older English. It would be ungrammatical (or barely grammatical) in Modern English, except in this phrase.

It is used as a stronger version of "Don't".

Answer 2

“Don’t (you) forget it!” is standard negated imperative. Making the subject explicit adds emphasis.

This looks a bit odd since it’s inverted, but that only happens when you have helper verb “do” for negation. The positive form looks more normal; in fact, the only way you know the emphasized form is imperative rather than declarative is the exclamation mark (or tone, if spoken):

“(You) forget it!”