I'm sorry you appear to have had a bad experience. You seem to be asserting that passengers were downgraded and then BA was charging people to pay for upgrades. That seems unusual. You also said that the flight was cancelled from TFS, but you were stuck waiting at Heathrow for more information. Were you meeting a loved one? Were you connecting at Heathrow and had a second flight cancelled?

Unfortunately, I'm not sure which airlines are immune to tired kids and crying parents, ground staff with faces not to your liking, or the possibility of cancellations? You will find people equally as upset with every airline in the world if you go to their various forums here. The LCC culture that's swept through airlines has come with the benefit of cheaper fares at the expense of better service, especially when things go wrong. You can imagine this wouldn't be better on Easyjet, Ryanair, Tui, etc.

I will note that I've generally had very pleasant BA experiences this year with excellent staff, both on the ground and in the air.