Always weirds me out to see an iMac running an OS older than OS X. The physical design language really ended up dictating the OS X look, didn't it? Still does, in a way, with Liquid Glass bringing back clear.
Aqua was garish and in your face, but it needed to be in order to be a symbol of what the system had achieved, which I think was especially important because that came at the cost of being a buggy, immature OS that had to run crucial apps in a hideous compatibility mode while it was getting established.
Edit: and if I can be a cranky old codger for a moment, I think that Liquid Glass unintentionally serves just as well as a symbol for what Apple has become: a company grasping to relive the memory of innovation without remembering how to innovate.