The Dull Men's Club group of facebook is actually oddly interesting. I would classify it more as a group who point out the very small oddities of every day life that are not very interesting. There is a post where someone saw two geese with 42 bay geese, another where the rental company fixed a door with a piece of pool noodle. Its more like a "huh that's kind of weird I guess" group.
One of my favorite books is The Mezzanine[0], which takes place entirely as a man ascends a single elevator but spins off onto all kinds of tangents that comment on and express exuberance about the most mundane things. There's an entire thread on the evolution of stapler design, elaborations on the invention of perforations, and abundant self-reflection. It's almost like a hybrid of Leonard Read's "I, Pencil" and Heg…
I'm not sure if it's the same thing as dullness though?