Excellent post where every sentence could be a separate stand-alone quote. I wish any team had such a UX expert whose nature is to question everything.

These people can be annoying, sometimes you feel like they are wasting too much of your time, but the truth is - those people are the ones who make a difference
They are the people who ask all the “what if?” and “why not?” questions. They disrupt processes when the process isn’t paying off. And they defy decisions, when the decisions don’t make sense. They may be subversive, but their goal isn’t subversion. Rather, they care. About the experience being designed for, and the people who will have to live with these experiences.
Shared publicly