Re: crash video with 30 min left at Thunderhill
All I'll say is that it's so incredibly common for cars to cut out to pass slower cars without full situational awareness (general statement, not an attack on anyone in this situation). If there is one thing to learn it's that you should always expect a car to pull out near you and have a plan to avoid. I've had people jump out in front of me way too many times like that, and I'm sure I've done it to others on occasion when my situational awareness wasn't great.
It does look like there was plenty of time and room for the white car to either have moved left, or slowed slightly to avoid being next to the red car once they came over. Regardless of whether the red car should or should not have moved over to pass, the white car could have avoided it. I did notice in the video from post #1, the driver did jump right into the blind spot of the red car for that left turn at 0:10, then either decide not to go for the pass, or couldn't, and had to back out when the red car came to the apex. If I was the driver of the white car I would have taken that to mean the driver of the red car wasn't watching the mirrors, or was driving more defensively and taken it to mean I should be more weary of them. But I'm not the driver and armchair comments aren't worth crap.
Best you can do now is just learn from it, rebuild, and come back with the knowledge of what to watch out for next time.