Added fake latency to a 200ms API because users said it felt like it was 'making things up'. It worked. I'm still uncomfortable about it.
The API call took 200ms. Measured it, verified it, fast as hell.
Three weeks after launch the client tells me users are complaining the results "don't feel right". Not wrong, not slow. Just don't feel right.
I spent two days looking for bugs. Nothing. Results were correct, latency was fine.
Then a user screenshot came through. The user had written: "It feels like it's just making something up. It comes back too fast."
The feature was a search over a knowledge base. In the user's mental model, that should take a second. When it came back instantly, it broke their model - they read it as "this didn't actually process anything."
I added a minimum display time of 1.2s with a loading animation. API still ran and returned in 200ms. User sees 1.2 seconds of "working".
Complaints stopped within a week.
The part I can't shake: the technically correct solution was perceived as broken. The technically dishonest solution fixed it. I explained it in my update as "improved feedback during result loading" which is... technically accurate.
Anyone else been here? Curious how others frame this to themselves - is fake latency just accepted UX practice or does it bother you the way it bothers me?