It really is so much better all round if you mention things to the crew. If they can fix it - great. If not, at least you tried, and you might get a customer service remedy at the end.

I had a broken divider on a recent CW sector which I mentioned to the CC serving me. Despite her efforts it couldn't be fixed properly, so she logged it in the fault book.

Following me contacting BA about this, I got 40,000 Avios.

You don't need to cause a scene to mention a problem. That's the only time I have ever had an issue that needed fixing on a flight.