Commas are crucial. There's a huge difference between
Let's eat, Grandma.
and
Let's eat Grandma.
You should be careful about inserting too many commas, as well. There was a book about grammar, titled "Eats, Shoots, and Leaves." The title is a reference to a sentence written about a koala; "The koala eats shoots and leaves."
Apparently some misguided person inserted extra commas to make this "The koala eats, shoots, and leaves."
Big difference.