Insane Mages and other Crazy Characters

This is something of a trope with my gaming group.  It started with one specific member and has sort of spread out from there.  The basic idea is that the character is so far outside of what is a normal experience that while everything they do works and make legitimate, if somewhat "other", sense, that they just seem bizarre and, well, crazy to outsiders.  At some point recently, one of us made the comment that my character, the insane mage of the game in question, seemed to be getting crazier.  To which the person who more commonly plays the type responded that all her characters seemed to get crazier as they went along.  This has led me to thinking about this seeming trend toward apparent flanderization.