When to worry about engine noises?

Oh yea I agree, I was paraphrasing the OP. Lots of people think that because it runs good it won’t have a problem and that can be very very deceptive.
Yup I get what you're saying. All good here. They can also run "ok" on 7 cylinders with an exhaust rocker laying in the head. lol. To add some humor to the thread, I once pulled the car into the trailer with only 4 plug wires on it. I thought, man that ran like crap, and started hard. But it ran NOWHERE near as bad as you would think with literally zero fire in 4 holes. Was just the Dummy driver that forgot to put the plug wires back on the plugs after reading.