Sometimes you want roles. You're not sure about Moose, Mouse, Moo and what was that damned Squirrel thing anyway? Then there's Class::Trait, but it has a funky syntax and the maintainer's deprecated it in favor of Moose::Role and you really don't care that it handles overloading, instance application or has a workaround for the SUPER:: bug. You think a meta-object protocol sounds nifty, but you don't understand it. Maybe you're not sure you want the syntactic sugar for object declaration. Maybe you've convinced your colleagues that roles are a good idea but they're leery of dragging in Moose (your author has had this happen more than once and heard of others making the same complaint). Sometimes you just want good old-fashioned roles which let you separate class responsibility from code reuse.