I tend to agree with this point, if not the spirit of it, but in that OO is generally supposed to be more disciplined and fringe behavior is discouraged...however I am reserving judgement based on the flawed ISA/HASA hierachy given in the OP. If this were fixed, maybe I would understand the examples in #1-#3 better. Nothing wrong with inventing a few new idioms...that is, if they don't introduce design/maintainance problems.

Given, discipline is very important. But also there is some "evil" in Perl that is also cool, because, yes, deep within us all, we know that sometimes evil is cool. It is for this reason that I like listening to Heavy Metal music sometimes :) No, seriously... sticking to form is important in OO, but OO is oft controversial as to what is 'good form'.

Over-use of singletons, factories, accessors, and other P.C. methods can be disasterous to an application -- just as 'evil' can. Both 'evil' and 'good' have their uses, and 'good' in the wrong place can have 'evil' results. Thus it is important to know both the good and the evil. It's a Taoist sort of thing. Ok, I just confused myself.... Carry on!