This is really good advice I also want to emphasize this when it comes to motorcycles for the love of God just take your turn at stop signs and lights do not wave them on. I have been apart of and seen people almost die from it.
I'm in Portland as well, and as a cyclist, it annoys me no end when a driver with no stop sign stops and waves me through my stop sign. I call them "niceholes".
My main transport is a bicycle. I do my best to be predictable, and obvious about it. And when someone tries to 'be nice' and let me go first when it's not my 'turn' / right of way, I start with all sorts of body language that says I'm not moving till after you do. Put my foot down, look at the sky, look 180 degrees away from the 'nice' car, look in the direction the 'nice' car is supposed to go, point in the direction they are supposed to go, shake my head point at the ground, cross my arms, etc, etc till they give up and just go. I've even had the opportunity to verbally explain the importance of predictability and Right of Way, but it usually doesn't go that far. LoL, we all just want to get where ever in the heck we are trying to get to, after all.