We humans are creatures of habit, and our favorite apps are part of our daily routine. When something we know well suddenly looks or works differently, it triggers all our survival instincts: loss aversion, fear of extra work, and just plain annoyance. Psychologically, this is normal. We rely on muscle memory (that old Slack shortcut!) and sunk costs (months of learning a product) and we instinctively defend the status quo. People hate feeling like they have to “waste” effort re-learning. We also spot downsides faster than upsides – negativity bias means users obsess over the annoying new bug or hidden button far more than they’ll celebrate that shiny feature.

Over time, people memorize where things live. If you shuffle menus or buttons (even with good intentions), it breaks that mental map. For instance, when Slack introduced a major new sidebar with collapsed sections and a ton of white space, many users complained it “hid” channels and made navigation three clicks away. They weren’t wrong – their habits were upended. Users have invested time learning the old interface. Any change feels like wasting that knowledge. The more complex the tool, the deeper the learning curve; power-users often feel especially protective. Veteran Basecamp users, for example, rely on its simple three-pane design. If Basecamp were to radically rebuild its interface overnight, even its loyal fanbase might bristle – because they’ve already paid the “training cost.”

Change often looks scary. People jump to “new = harder,” even if it’s better in the long run. A redesign feels like a pop quiz they didn’t study for. (That’s why so many gripes about new designs focus on eye candy and “busy” layouts.) That’s also why Slack’s 2023 redesign – which stuffed chats, threads, and notifications into ambiguous “Home” and “Activity” sections – went over poorly. Users felt the new nav was more confusing, not simpler. We hate losing what we know even more than we like gaining the same thing. A user might grudgingly agree the new dark theme “looks nice,” but they’ll still complain if it means a momentary struggle to find the search bar. The mind hones in on everything lost or new friction. For SaaS apps, even small layout shifts trigger this: a button move or color swap can inspire a disproportionate outcry.

People often reject change not out of stubbornness, but out of self-protection. They’ve built a comfort zone in your app, and any big shift feels like a bet on an unknown. Real-world examples abound: Slack’s most recent overhaul tried to declutter, but power users objected that it hid essential info behind vague tabs. (Those users just saw their carefully organized channels vanish into “Activity” – automatically triggering instinctive panic.) By contrast, when Basecamp has adjusted its UI over the years, they’ve done it so gradually and transparently that it rarely makes headlines. The lesson? Whenever possible, treat users as partners: explain why you think a change helps, involve them early, and never underestimate how attached they are to the current version of “their” app.