I forced every engineer to take sales calls and they rewrote our platform

> At the end of it, they were sketching a completely different architecture without my "PMing". Because they finally understood who was actually using our product.

I cannot help but read this whole experience as: “We forced an engineer to take sales calls and we found out that the issue was that our PMs are doing a terrible job communicating between customer and engineering, and our DevOps engineer is more capable/actionable at turning customer needs into working solutions.”

Or engineers are little bit full of themselves and know better how user should experience the product. If user is "holding the product wrong" it is a problem of a user and not a problem of stupid design, created by a person who knows in which order these buttons should be pressed. People around Desktop Linux could write a complete book about dismissing user's complaints.

The moment you have stubborn engineer who knows better than PM and user, it is really difficult to get anywhere. However if you will put such engineer into line of fire from a users that's suddenly not engineer's friendly PM trying to tell the engineer that this is wrong, these are frustrated people who would like to skin engineer alive as a punishment for using his "awesome" creations! That induces fear, but absolutely also crushes his ego, because somebody is berating product of engineer's genius like it would be a retarded hamster.

From my perspective, it is not about showing that PM is an idiot, it is about humbling your engineers. Their ego will grow again and this exercise will need to be repeated.

God forbid an engineer should have an opinion on UI/UX.

I have long believed that the biggest issue here is that engineers and power users generally have a much higher “pain threshold” when it comes to poor or complex UI/UX. They are not always the best people to judge how or if less experienced users will tolerate or adapt to those patterns. It’s fine to have opinions but they must be prepared for them to be challenged. Even better if they can invite others to challenge them, which is essentially what talking to your users achieves.