Hi Maarten. I don't mean to imply that there is no value in making mistakes. I think that the Agile community takes it to an extreme.

Mentorship is just as important. People don't want to make mistakes. Of course they will, but if I made one, and I knew that the team lead watched me do it, I would be angry: I would want to know why they did not warn me.

I also worked at several startups, and I launched one as well - it grew to 200 people. My role was CTO and it was my job to make sure we did not make big mistakes: if we did, it was very costly to us. A big mistake can put you out of business. We did all our work fixed price - so we were on the hook for things working. And it was big, complex stuff.

The approach I used was that whenever a team started a client project, I would get them all into a room, and ask them how it would work. I would talk them through the things that could go wrong. The meeting ended when I felt that they understood all the potential problem areas: they did not have to have all the answers, but they had to understand the problems.