I recently used a legacy win32 app at work, on a windows 10 laptop. It looked old, even though the buttons etc got styled the win10 way. Since the app had some issues, I wanted to rule out a compatibility problem with modern Windows, and ran the app in a windows XP VM on the same laptop. Unfortunately the same issues arose, but I was really surprised by how snappy the app felt. Everything was just immediate, sub-windows popped up instantly. Sure, the machine was an order of magnitude faster than the typical XP machine back in the day, so it's not an apples to apples comparison, but still it was one of these revelations that we just seem to be taking one step forwards and at least one step back every time we improve something.