The overly nice factor can be very annoying at times particularly when you are at a 4-way stop and someone thinks they are doing you a favor by letting you go first and holding everyone up and actually causing more delay.
From what I understand it is illegal to honk your horn in Washington State unless it is an emergency.
About the weather. I remember a time in the late 90's when it seemed to rain hard for over a week without ever stopping. I was constantly wet everytime single time I went in or out, day and night. (Remember that Seattlites DO NOT use umbrellas. Only business women in suits, couples in tuxedos/fancy dress and tourists use umbrellas)
The rain is not all that bad (however, this year is pretty bad) but it is difficult for people to transition from warm weather places. i.e. Cali, Arizona, Texas, the Southeast, etc. You really cannot ask for better weather in the summer and spring seems to come earlier every year. I think it has a lot to do with mentality. People I worked with in Southern California expect to play tennis everyday or go surfing in December. That's not happening here. In Seattle it does not get dark until just before 10 pm in the summer.
As far as the OP the Starbuck's location is not as exciting as downtown.