A bit of a soapbox post here, sorry in advance
Part of the problem with transit etiquette is that I think Metro Vancouverites are not that experienced in the interaction of dense, urban settings. We've been accustomed to large personal space and low density living until recently, where there's been the draw and the allure for people adopting higher-density lifestyle.
This means there are going to be more people that just don't know how to act 'in public', whether it be consciously or not. I think many don't realize what they're doing, they are only doing what they would do in their own private vehicle or in their own home.
Another part of the problem is that we live in a generation where etiquette is not necessarily considered a positive attribute. Think of words like conformity and social rules. We live increasingly in a world of me-comes-first. Phenomena like Twitter, blogs and Facebook are manifestations of it. Ironically, caring about what other people think of you often means showing you don't care what people think of you.
Anyway... personally on public transit, I like it quiet where people don't talk too much or too loudly. I don't want to hear other people's conversations so why would they want to hear mine? You guys all know this, it's so simple. Do unto others as they would do unto you.
Keep in mind however, no talk does not mean no interaction. Things like smiling, nodding, moving your body, polite gestures are all examples of non-verbal body language that goes a long way to making transit an enjoyable experience.
Things that I personally am not really that comfortable with is eye contact and any body contact. But I see nothing wrong with that either really. Maybe that's another reason why Vancouverites seem so 'cold'.