I don't see Furio as a nut at all. Paulie however, is a little nutty. I love the episode with the lawn guy too.

Remember the episode where Paulie is at a Starbucks type place, and comments about how "we invented this stuff, and they're making money."
Furio is much more intimidating than Paulie, yet Paulie is obviously dangerous as well in a comical way.
TIS