We landed around lunchtime on a very foggy day in Vancouver.
Transiting at YVR was simple enough. Unlike the USA, Canada does have international transit facilities. I went to the transit counter, where I had to put some details into a kiosk and then wait for all the other connecting passengers from my flight to show up so they could take us through security together. There ended up being around 20 people from my ICN-YVR flight who were connecting onwards to MEX - who knew that this is a reasonably popular connection.
After clearing transit security, I had about a 5-hour wait before my next flight. I was very much needing a nap at this point, so went to the Maple Leaf Lounge (which I could access with Star Alliance Gold). This was absolutely heaving, had a lot of sunlight coming directly into the lounge, and didn't have any suitable spots for napping. So, I walked out and tried the SkyTeam Lounge again (which I could access with Priority Pass). This was much quieter and had a few private pod seats, but these weren't really good for napping either.
In the end I just got some noodles and had a shower in the SkyTeam lounge, then tried to find a quiet bank of seats in the terminal to lie across - but didn't really manage much actual sleep. I ended up returning to the Maple Leaf Lounge for some food before boarding.
My YVR-MEX flight on a Boeing 737-8 was completely full. It's a six-hour flight, but being an intra-North America route, the only free food served was a cookie. Food is available to buy on board, but I didn't order any food during the first service. By the time the crew did a second trolley run, the only fresh food still available was an overpriced pack of vege sticks with hummus.
Air Canada does at least have seatback IFE and Wi-Fi, but honestly, this was not an enjoyable flight. Especially as I was really overtired by this point.
We landed around midnight local time in Mexico City. As I was walking from the gate towards immigration, the lights all went out inside the airport terminal. They came back on a few minutes later, but this pretty much sums up the current state of MEX airport, unfortunately.
There was a very long wait for checked bags, and it was already 1am by the time I got into an Uber to my hotel for some much-needed sleep.