Deleted my previous comment, felt like I should give this a bit more attention.
To be honest I feel like all designs are good in their own way. I like the general vibe of Memphis, but being that I was born in the mid 90s, it's probably just that general energy you get from things that happened before you did, where they are "cool" due to how just-old-enough-to-be-old-but-not-old-enough-to-be-an-antique they are, yanno?
Y2K design -- Well. I like the transluscent plastic on Gameboys and Macs. Really underrated aesthetic, wouldn't mind having it back. The DreamCast had some very sleek angles too.
Frutiger Aero will never not "look like the future" to me. It was the age of computer interfaces having all sorts of fun colours and transparencies and animations, and it just LOOKED futuristic and neat. Don't care for the product designs of the era though. That shiny finish would draw in filth and fingerprints from accross the room and after a very short time it'd lose its prettiness.
Flat design I have issues with, like the hamburger menus and the abandonment of descriptive text in favour of abstract icons -- It is also a bit too serious, but I understand and accept that, even if I miss the playfulness of Frutiger. -- But it DID finally bring us dark mode. And my eyes are forever grateful.
... Just wish solarized themes were the norm instead, no idea why they must have such high contrast. I'd even give light mode its time of day if it was a solarized light instead.