Common courtesy has its limits. An hour long flight, I'm sitting in F, a man who was brought to the plane by wheelchair is having trouble making it to the back, I'll offer my seat. (Have done this.) That's common courtesy.

A four hour flight, I'm in an Exit Aisle, and the man sitting behind me whispers in my ear that it would be great if I did not recline, as his prosthetic leg could not bend in a comfortable position if I reclines. Problem solved. We switched seats. That's common courtesy.

Pregnant woman with carry-on bag. Lifting it into the OH is common courtesy. So is letting the person sitting farther behind you on the plane get in front of you in the boarding line, so the person doesn't have to wait behind you while you sling up your suitcase and store your computer bag. (Have done all these things.)

A sixteen hour flight where people who have chosen to fly with a baby asking for everyone to change plans to accommodate their choice exceeds many people's definition of common courtesy. In any event, the common courtesy that was most violated here was the FA's common courtesy of being polite when making a request and gracious, even when not getting the answer she wants.