As an atom absorbs energy and new electrons are added, the electrons fill up the "seats" one by one, beginning with the most desirable "table" - the ground state - and working outward. This is the Pauli exclusion principle: once an electron occupies a seat, it excludes others like itself from sitting in the same seat. (There is no lap dancing in electron land.)
Bosons, in contrast, have serious boundary issues; lap dances are de rigeur. They love to crowd together in the same space. Why, they'd turn the entire Subatomic Cafe into one giant mosh pit given half a chance! You and the other fermions click your tongues in disapproval at the grotesque lack of disciplined order on display.
But at least everyone knows their place, and sticks with their own kind. The Subatomic Cafe is unapologetically segregated in that respect. Anyons upset the rigid quantum social order; they refuse to choose a side. They can do that because - at least to date - they only "exist" in two dimensions. That's right, the Subatomic Cafe happens to be part of Flatland">the proverbial Flatland.
It might seem silly to talk of two dimensions, since we occupy three-dimensional space (and a fourth dimension of time). As Wilczek explained to Science Watch back in 1991:
Experimentalists can make substances - as can nature, for that matter - that are very planar in their structure. Graphite is a good example. It's very easy for electrons in graphite to move within a plane, but difficult for them to jump between planes.... Therefore, inhabitants of that plane effectively live in a two-dimensional world.
So yes, physicists can create two-dimensional systems in the lab. And two-dimensional worlds play by their own rules. "Fermions and bosons are the only possibility if the dimension of space is three or more," Wilczek explained back in 1991. "If the dimension of space is two, however, then there is a continuous range of possibilities, and those are the anyons."