Read the manifesto. It literally says handful of almost completely meaningless, unimplementable things.

Any attempt to actually take that and turn it into something is destined to be sharply divorced from reality.

But the real fun comes when you do "white water rafting" style development. This is when there is all the ceremony of "Agile" (read: a "fast paced environment") with all the planning of waterfall and absolutely everything is top priority. You and your coworkers are constantly thrown around trying not to smash into rocks or capsize the boat, meanwhile being pulled violent in every direction. Somehow you continue to make your way down the river eventually with fewer and fewer co-workers as she casualties mount.

Fun times.

The actual methodology is completely irrelevant. Working under terrible management is terrible. Working under terrific management is terrific.

But in even those cases, it was largely replaced by Spiral, which is similar to agile and pre-dates it.

Edit: Spiral is like going down the Waterfall two or more times. Similar to agile, but formally documented, with management and customer sign-off up the line, and with a much longer cycle time.