The rule I learned is that a sentence with a single subject but a compound predicate that’s joined together with a coordinating conjunction must have no comma:
- I went to the lake but did not catch any fish.
(one independent clause whose subject distributes across two verbs joined with a conjunction)
That rule states that a comma should be used only when two independent sentences are combined with a coordinating conjunction to create a compound sentence:
- I went to the lake, and I saw a duck.
(two independent clauses, each with its own subject and verb)
However, I see this rule being broken time and again by popular writers where a complex sentence with a coordinating conjunction is separated by a comma. I take it that this rule, like so many other English “rules”, has room for exceptions.
So, in which cases can this “rule” be broken?
Edit: I'm reading a book called "Known and Strange Things: Essays" by Teju Cole. In this book I saw a sentence that read "I'm not superstitious, and thought nothing of it." "Thought nothing of it" is a dependent sentence joined by a comma with the previous independent sentence.