The other day I was riding the SkyTrain - yes, I know, completely out of character, but bear with me - and, while the train was waiting with its doors open at Commercial-Broadway Station, I overheard a tourist asked someone near the doors if this was the train to the airport. I assume that he was a tourist because 1) he had an Australian accent, and 2) he was looking for directions to the airport. As it was, the person he asked just said no; had it been me, I would've given directions.
For those of you playing along at home, the simplest way to get from Commercial-Broadway Station to Vancouver International Airport by SkyTrain is to ride an Expo Line or Millennium Line train to Waterfront Station and transfer there to the Canada Line. Riding to Granville Station and transferring to Vancouver City Centre Station is also acceptable, but not quite as direct.
Nevertheless, you'd think that if you're a tourist in a strange city, you'd make an effort to at least know how to access the airport via public transit, as it's a rather important destination. It's not as if the SkyTrain is complicated, either - the bus system is one of the most chaotic and difficult-to-understand I've ever used, but the SkyTrain is straightforward and simple. In my book, familiarizing yourself with the basic methods of getting around a city you know you're going to visit is just good sense; just like if you're travelling to a place that speaks another language, you should at least know how to say please and thank you and how to order beer.
Because, really, I've always believed that the point of going to new places is to come to a greater understanding of both the new and the old - in addition to what you discover about the place you've journeyed to, that knowledge can be placed in context with what you didn't know before. Without that proper context, knowledge is inert - travel and trade and interchange with new perspectives is what's required for dynamism and growth. Compare the trajectory of the independent and perpetually squabbling Greek city-states, for example, with that of China under, say, the Qin Dynasty.
A lot of this, I know, comes from my own biases shining through. When I landed here, aside from how to reach the airport and hotel I didn't know very much - but after a couple days of just wandering around downtown and more outlying areas, I built a map for myself. I'm well aware that my adherence to the wandering ethos is not universal. Even then, though, there's nothing stopping a misdirected tourist from writing "take Canada Line to airport" on a piece of pocket paper - then the question becomes, much more directly, "where can I transfer to the Canada Line?"
Like I said, though, it's easiest at Waterfront. There, at least, you don't have to go outside.