Where to start?
First, you can't check in for an international flight (transatlantic) on the BA web site until 24 hours before flight time. No seat assignments until that point. Tried to do that, the utterly useless BA IOS app refused to allow me to do anything. So I called them (Indian call center). Sorry, can't help you. At the 24 hour point the ability to assign seats is "out of our hands" and in the hands of the agent at the gate (24 hours ahead? At the gate?). Sorry, can't help you. That's all. The South Asian call center people are incapable of doing anything that isn't on their flow chart. Same with almost any customer service for any company that uses India/Pakistan customer service. Zero individual initiative. If it's not on the flow chart, sorry.
Then they randomly cancelled my Lisbon-London flight without telling me. When I tried to check in for it, it wasn't on the BA app under "my trips". I called them, and was told that they couldn't help me, since the booking site had used American Airlines "ticket stock" (ticket stock, in 2019, seriously?). So I spent an hour and 15 minutes on hold waiting to talk to someone at AA (my alarm was set for 0445, and I discovered this about 2300). To her credit, the woman at AA did find my reservation (after being on hold with her for another almost 45 minutes). She said there was no reason that BA shouldn't be able to see it, and no reason that she nor her supervisor could think of that BA would have told me to call them. She said the reservation showed that it was confirmed. Called BA back to make sure, and was told that without the record locator number they couldn't' help me. Turns out they created separate record locators for my PHX-LHR-LIS segment, another one for the LIS-LHR segment, and still a third for the LHR-PHX segment. I didn't have either of the last two in anything in my possession. And BA claimed it is incapable of pulling up any reservation without the RLN.
Soooo....I got to the airport in Lisbon yesterday morning, got on the flight to London where I had a 4 1/2 hour connection (Terminal 3 to Terminal 3). My roll-on was too big for the overhead bins on the A320, so I checked it through to PHX. Lisbon to London, Terminal 3, London to Phoenix, Terminal 3, four and a half hours later.
Got to Phoenix last night (after having been awake for going on 30 hours), no bag. It was in London.
The flights themselves were fine. Cabin staff were very nice. It's just everything around all that, British Airways is a bunch of utterly incompetent boobs.