I did the same thing just a couple weeks ago. YYZ to MUC flight. Wife and I in 5 D/G on the smaller 788. The woman in 5A was terrible the entire flight. It started with her complaining about the lack of window. Then about how her meal choice was gone. Before long it
morphed about how she’s got so many choices and she’ll never fly air Canada again, what’s your name, do you know who I am, etc. The poor SD did an excellent job. He must have spent an hour of the flight dedicated to this one woman in particular. I was sitting beside her in 5D and told the service director multiple times loudly how he is such a saint for having to deal with such rude passengers from time to time.

Wrote in to defend him because I’m certain she was out for compensation. And if she didn’t, then hopefully he gets a gold star somewhere from the email because he was great.