Is the comma in “Stop trying, it’s just sad” an acceptable use of the comma?

Answer 1

No. This is technically a compound sentence. "Stop trying" and "it's just sad" could both stand alone as two separate sentences. They are independent clauses. You can separate them with a period and a capitol letter. To join them into one compound sentence you have 2 options: a comma and a conjunction or a semi colon. You could also add a subordinating conjunction and turn this into a complex sentence. This

Option A: Stop trying. It's just sad.

Option B: Stop trying, and it's just sad. (awkward)

Option C: Stop trying; it;s just sad.

Option D: Stop trying because it's just sad.