I was going to argue, then I realized you were just venting.
When an argument has become a venting session.
Chinese original
我本来想反驳,后来发现你只是在表达情绪。
Why it works
The reply changes the label of the conversation from debate to venting. It can feel dismissive, so it is a poor choice when reconciliation matters.
Original source unverified; not attributed to a historical author.