In other words, let your characters change, as life will change them;
please do not change them for no or insufficient reason.  That is OOC.

Any agreements/disagreements?

        I agree with you, Stormwalker.  Certain events, traumatic or
otherwise, can change a character to such a degree that they become OOC.
Who is to say that characters MUST stay IC at all times, even if a tragedy
had happened?  

        Do you think Ranma would stay IC if he suffered severe psychological
damage?  What if he had gotten raped in female form?  Do you think, just
possibly, that Ranma's general personality and outlook would change a shade,
or two, darker than before (if that happened?)

        What about time?  I'm sure people remember their grade 9 years, and
with the benefit of hindsight one can ridicule and scorn themselves for
stupid things one did while younger....but you've changed.  You've grown
older, and (hopefully) wiser.  You've broken the so called IC mold of your
former self (IC as in that you know that a certain stupid thing you do now
would have been IC with your younger self) and assumed a new IC one.  

        I find it helps to explain why the character is OOC (in your story).  

"Don't call me Stormy!  I hate that name!"

Hello Stormy! (WebDragon runs and hides)