I know all these areas very well, grew up in the Willow Glen area. So I can address the specific areas you are talking about.
As far as the examples given, only thing you can controll in any situation is your own behavior. I like to look for ways my actions could have changed the situation for the better. So I will approach it in such a way.
#1 > Coleman is a fast moving road, typically +10mph over the posted limit. If the car coming behind might have to use its brakes to slow for you as you take the lane, you might want to consider waiting for them to pass before moving over. Someone can easily look down, not see you move and then have to slam on their brakes. You have the right to the road, but if you had slowed and waited for the car behind you to pass, you would have avoided having any issues.
#2 > Downtown Willowglen is usually fine for cyclists taking the lane. You just happened to be in front of a jerk. If I am aware a car is behind me then I do move over to the right and give them room to pass. I typically avoid downtown WG though, and use the side streets. Lots of nice houses in that area to look at. While the streets are narrow and bumpy, you at least avoid all the traffic of DT.
"Is this normal? Or have I just been unlucky so far?" In my experience, no its not. However I do not subscribe to the taking the lane philosophy. In talking to some friends who do keep to that philosophy, it seems to be very normal. I have been yelled at 3 times in 3 years after moving back to San Jose, while my budies who take the lane more frequently have weekly stories to tell.
My personal opinion is that taking a lane is done when you are as fast or faster then automotive traffic, when merging to the left lane to turn, or when the right side of the street is obstructed or hazardous. I believe the most dangerous place to be is in the center of the road, when does a driver who hits a cyclist say, "I saw them, but decided just to run them over anyways." Its always, "I didn't even see them." They say that regardless of where you are. I have been rear ended in my car while at a stop light that was red, and seen people drive straight into cars stopped, "Oops didn't see ya there 3000lb SUV." I just don't trust that being in direct line of sight is any better than being slightly off to the side as far as visability, and it sure isn't better if they fail to see you at all.
Best course of action is to pick routes that have minimal traffic, and maxiumum bike lanes. There are lots of great routes in the area, and more so if you decide to head out to Los Gatos or Saratoga.
I did think of a time I do take the lane, when climbing tight mountain roads. In that case I do use the entire lane, but move to the right as I hear a vehicle.