Stop protecting your characters: trouble in fiction

I did my PhD at University of Southampton, supervised by Peter Middleton. Peter warned me over and over that I protected my characters too much. I had a scene with two characters driving in a sports car, and one got sick. The driver managed to pull over to the side of the road before she vomited.  I always remember Peter telling me that I was even protecting the car!

Since then, I’ve tried to approach writing in terms of how much difficulty I can throw at my characters. I tell my students now that I want them to be happy, healthy, loved, and to have fulfilling occupations and nice places to live because they are my students and I care about them. However, I always follow that up with the fact that I don’t want their characters to have any of these things – because happy characters are boring characters!

And here's a picture of my protagonist Max's sports car, even though (as yet!) no one has vomited or bled inside it...