Honestly? Any of them except the last one. My preference would be 2005-2015, but any of them is better than what came after. Late 2010s was alright, but around 2020 you can really tell UI designers got their marching orders.

It's all so damn boring and lifeless. Rounded corners on literally everything for no reason other than trend chasing, wasted space and needless gaps between elements, white OR black - rarely anything else, lest it interfere with whatever systemwide adaptive coloring thing is running (even if there isn't one), boring and lifeless icons/logos, an obsession with "clean" and "streamlined" that effectively equates to the removal of usability for aesthetics, etc. All of it copy and pasted to every single piece of software or app or site.

Its ironic you put Corporate Memphis images next to it in the 2015-2024 section, because that is effectively what this trend in design aesthetic will be remembered as.

Bland, lifeless, safe, focus-grouped garbage, implemented by companies that have reached a point where the innovation is dead, corporate consolidation has effectively destroyed any room for something new and original to enter the space, and the only thing they do anymore is trend chase. Even the slightest bit of originality or doing something different from the market leader may risk the potential loss of a sliver of shareholder profit, and that simply must never be done.

And I swear to God, if I hear one more focus group generated argument about how rounded corners are more inviting or human, I am going to break into your home, and personally change every last single doorway into a hobbit hole, and every window into a port hole.