I really don't understand why some try to sweat out the details in minimizing the time they need to spend at the airport as it's like some sort of competition honestly. Last week we were flying home from IAH to AB and witnessed a traffic jam just to get into the lane to head for departures. We had business class tix and so had access to the Premier Access for luggage check-in and security (which was the easiest and quickest check-in we ever had). But we still saw a gentleman denied check-in as a Premier passenger as he attempted to drop off his luggage - even though the flight had not left, the gate was closed - he said it was no fault of his own that there was a bottle-neck at the departure lanes but he was still at the airport before the flight left.
On our recent flight from YYZ to AB direct flight, we arrived at least two hours before and still, it only allowed us about 10 min breathing room before boarding started. There are so many factors to take into account, that for any long-haul or cross-border flights, two hours is more of a minimum for us. Why begin a holiday stressing out about making sure you make it through to boarding on time that as soon as a person gets on the plane, he or she needs to use the lavatory as they didn't have time before boarding - lol ...