Difference between Don’t you forget it and Forget it

don’t you forget it—an admonitory phrase used after a statement to emphasize the idea:

• If it wasn’t for them, we wouldn’t have all this, and don’t you forget it.

forget it—(imper.)

1. take no more notice of it; don’t mention it:

• “What do I owe you for lunch?” “Forget it.”

2. don’t even think about it:

• If you’re expecting a description of what those thugs did to us, please forget it.