Behind the scenes of shipping a client web app: the most useful test I run now is sitting quietly while a real user clicks through it for the first time. Every single time, they tap the thing I thought was obvious and miss the button I thought was unmissable. Last week a client spent two minutes hunting for a setting that was one click away, because the label made sense to me and not to them. No amount of internal QA finds that. The fix is almost never a new feature, it is renaming a button, removing a step, or moving the thing they need to where their eyes already go. Ship the app, then watch someone use it. That is where the real build starts.