Actually no, I hated the Vista era UI design. Linux themes were positively garish, add MacOS looked like a candy store. CDE greatly impressed me back then. It looked like it was made by adults for adults. Highly legible, and the pastel colors are being emulated by Solarized.
I'm sure that those UIs were a product of the times. The 90's and noughties were loud and colorful and exciting and everything looked like a comic. Now that we live in more depressing times, we can look to the science of perceptual psychology.
You see, we have an attention budget, we need to process what we see. Visually complex UIs need to be parsed, and that takes mental effort, and that robs us of mental energy to focus on our work. It's not a crippling effect, but it's there.
Look at street signs and corporate logos, they easily lodge in our mind. Effective advertising has a clear and simple visual language, and this is what UIs should strive for.
Show the rest of the comic - I dare you!