One of the worst kinds of bug is the one that never throws an error. Everything looks fine. The logs are clean. And the data is still wrong.
I ran into this on a subscription billing flow for a client. Stripe would send a webhook when a subscription changed, and my handler was supposed to sync that change into the database. Except sometimes it did not. No crash, no red text, just a subscription that quietly stopped matching what Stripe actually said.
The cause turned out to be duplicate products in the Stripe account. My sync function looked one of them up, found a match it did not expect, and returned early before doing the real work. It failed silently, which is the most expensive way to fail, because you do not find out until a customer does.
The fix in the code was small. The lesson was bigger. When a function bails out early, it should be loud about it. A log line, a thrown error, something. Silent success paths that are actually failures cost far more time than a noisy error ever will. Now I write handlers that complain when something looks off.