Prescriptivists vs Descriptivists
Prescriptivists think the language belongs to them, or a least they hold it hostage for "purity"; Descriptivists know that the language belongs to the people who use it and are delighted by its fluxuations. A good writer knows the conventions of his language and how to use them. A great writer knows the conventions of his language and how to break them--a sort of literate terrorist.
I try hard to write good, occasionally (read rarely) I write well--but never great. Now, could someone tell me why my stylus doesn't work on my Sony Reader?