I can share a post-mortem in a non-confrontational way and have a discussion about it. Even if it often results in an “Oh well, I guess it won’t work”, sometimes it’s a highly productive conversation on how things could have been done better, and the person or team goes off to execute some new variation to great success. And sometimes the variation fails as well, but such is life. I try to engage with people in a way where even if failure is highly likely, we go in eyes open knowing the risk is worth it. Sometime we’re wrong (or I’m wrong, it’s my fault) but such is life. Not all shiny ideas keep their shine once they’re unpacked into an attempted implementation.