Oh so many, but particularly about planes, what with complicated family/work arrangements in different countries:
The very elegant middle-aged man next to me and my 3 boys aged around 5, 3 and 1 on flight from Rome who looked up, said completely deadpan "I've got 5 children" and went back to his newspaper.
BA air hostess on flight from Beijing with ds1 aged about 2 months who upgraded me, and spent most of the flights bringing me snacks and holding ds for me so I could go to the loo etc.
All the air hostesses on Air China who always take small children off and play with them for several hours on planes, and just laugh and say 'how cute' while the kids bomb up and down the stairs into business class etc. Deffo best airline for long haul with a toddler.
The gate staff at Fiumicino who ushered me into the plane with a first-aid kit while the cleaners were still hoovering it, because ds1 had fallen over and whacked his head in the check-in scrum as I got all flustered trying to handle the pushchair and ds2 and 3. I cried that time, but it was all OK in the end.
Airline staff who understand that you need a pushchair at the plane, not the carousel, when you have 3 small children all asleep on landing and you are on your own.
My youngest is 6 now, and flying is dead easy, but I have some battle scars!!