It's generally recommended to use a comma before "and" when connecting two independent clauses, but it's not always required. Here's why:
* The "and" rule: Using a comma before "and" is a common way to separate two independent clauses (sentences that can stand alone). It helps the reader understand that there are two separate ideas being connected.
* Example: "The dog barked loudly, and the cat hissed back."
* Exceptions to the rule: There are times when the comma before "and" can be omitted:
* Short and simple clauses: If the clauses are very short and simple, the comma might feel unnecessary.
* Example: "She ran fast and won the race."
* Emphasis: Sometimes, the comma is left out to emphasize the connection between the two clauses.
* Example: "He didn't know what to say and just stood there."
Ultimately, the best way to decide if a comma is needed is to read the sentence aloud and see if it sounds natural. If it sounds choppy without a comma, then use one!