[blub]

An effective retrospective requires creating a safe environment for sharing ideas and a SM which can foster such an environment.

I am guessing that such an environment is quite rare, hence the percieved lack of utility of the retrospective.

I can speak from experience that this is very hard to do. I expect that I will have to deal with a brewing technical conflict in the team soon and I'm not sure what's the best way to do it. I've also seen what happens if such coflicts are sweeped under the carpet and it's not nice.