Pete, the shoulder check you should have done is sometimes referred to as the 'lifesaver look', which is actually better than using a mirror.

Because of videos like these from Heze Chinese car drivers mostly all stop at 'super long to cycle through' traffic lights these days, like a bad parent telling their child what to do because 'it's safer and is the law/rules' but not explaining the underlying reasons why. Their perception is that not obeying traffic lights causes accidents.

A red light - making me stop mostly for no reason, when a yield and look would have been enough, a green light trying to convince me it's safe to go through the lights without looking at a normal speed. I view them both red and green cynically.