Why is Crater Lake a must-see?

To really appreciate Crater Lake you need to do the Rim Drive and take one of the boat tours. I've done the Rim Drive several times, in a car and on motorcycles. Just driving up to the edge and looking down on it and then leaving won't capture all of it's uniqueness. The boat tour is very informative. It's amazing how many water falls and streams flow into the lake. I guess it's like anything else, it's what you make of it as to what you get out of it. There's also several hikes in the area that will get you a gorgeous view of the lake as well as Diamond lake that's nearby.
I've lived in Oregon all my life and still never get tired of going there. Maybe it's living in a state that's wilderness oriented that makes me appreciate the outdoors.