There are common rules of courtesy many drivers observe. If a car is pulling out of a parking spot or driveway, you let them in IF IT'S SAFE TO DO SO... aka when you're stopped at a red light and then traffic is starting to go. Most drivers do pull out but if they aren't paying attention and look like they're not going to go, then I'm going to go. What's not safe is suddenly stopping for no reason*.
Also, most people here let one vehicle merge in on a freeway. 99% of the people around here do this... it doesn't slow down the flow of traffic on the freeway by much and people can actually get onto the freeway. This is provided that they are merging in at the same speed as freeway traffic (whether 18km/h or 80km/h), some drivers merging in are stupid (or maybe just don't know about what could be a common courtesy rule only known in Vancouver) and just come to a dead stop on the on ramp, some think they can butt in with the car in front of them forcing a freeway car to let two merge in, but overall this is how it goes in Vancouver.
I put a * because of pedestrians. When I see a car stopped at an unsignalized intersection, even if not officially marked as a crosswalk, legally pedestrians are allowed to cross at any intersection so I will NEVER overtake a vehicle stopped at an intersection at full speed. I always slow down to about 20km/h, see if there are pedestrians crossing or if the driver is just being a douche and not signalling a left/right turn, then proceed. If I am stopped at a crosswalk to let a pedestrian cross and see in my rearview mirror that there is a car who's not about to stop, I will beep my horn to alert the pedestrian of the incoming danger.