Vegreville posts several very nice thoughts, and links.
Why being an academic is pretty great
I agree most, perhaps, with these reasons why being an academic is fun:
3. It's great to see a student suddenly understand something new.
4. It's great to understand something new myself. Learning is fun, and that is what I mainly do.
I almost always teach at least one overload class. If you don't like teaching, what are you doing?
Does it hurt my research output? Probably not. Being a chairman is a lot like a full lobotomy (except the scars last forever), so my research output is hardly impressive anyway.