Running is pretty mundane. But so are many things that people enjoy (like you said). It might sound wishy washy, but running this much has shown me so much of the world I wouldn't ever trade what I do. Hell, once this winter is over I'll probably be doing it again. Consider this.
I get to travel to places I've never been so I can run, family members that would never leave their small town choose to follow me and we get to see so much stuff we wouldn't otherwise see together. I can pretty much eat and drink whatever I want so long as it settles in my stomach well. I can jump into any race at any distance with a friend on a moments notice. I can take the same amount of time that a student spends after school at a sports practice or piano lesson and just run. Listen to a podcast or book, if indoors play some video games on the treadmill or watch Netflix. I can meet others (faster or slower than me; could honestly care less) and just have fun.
Sometimes running 100mpw isn't a means to an end but it's just something you do because, why not?