As well it should. Because now things that used to take three seconds will take 15 minutes for a month until you learn the new interface.
The designer will respond that yes, but then once you learn the new thing it will take two seconds. And if you save one second twice a day then you'll have made back that 10 hours you spent learning the new thing in less than 50 years!
Except that they're going to change it again in less than 50 years.
And that's assuming that the new design is actually better and not just different or worse, because also, this:
https://news.ycombinator.com/item?id=25950351
Rule of thumb: If the new thing isn't better enough to cause people to switch to it voluntarily without any prodding or the removal of the option to use the old thing, it isn't better enough to be worth it.