I've run into gen-z people talking very nostalgically about 2000s UI design trends. They've even retroactively dubbed the era as 'futiger aero'.
I'm a bit older and don't as fondly remember that era; I remember a lot of excesses like nonsensical reflections and calendar apps with leather textures. The 2013 turn to "flat" design felt quite fresh to me, and I haven't really gotten tired of it yet.