Air Canada -- lets see, in the last 10 years:
1. lost my wife's luggage from Calgary to Toronto, then lost it again 2 days later from Toronto to Halifax. Nothing better than an outsourced call center in India that didn't know where any of these cities actually were.
2. put all 4 of us in different areas of the plane -- when our kids were 2 and 4. Would have been great for us, not so great for the people next to them. Had to wander around the plane begging for people to move. nice.
3. and one of my favorites, we had just dropped our luggage off for a trip from Calgary to Toronto -- I get a phone call from a WESTJET employee asking me about my bag -- it had been put on a Westjet pullman or something, he then put it on the right flight for me -- now that was memorable!

And about a million other stories from others I know about horrific Air Canada policies and service. 

We only fly Westjet now, not always perfect, but 100x better than AC.