During the Wrath of the Lich King years this was never much of an issue for me. My RP main, Avanda Everfrost (and later Shadewind), was a personality much like my own: a planner and politician rather than a fighter, someone who preferred diplomacy to battle. She could get plenty worked up over personal business but remained coldly dispassionate about politics and world events. I was mostly content to let her have the lead; we thought much alike and I never had a problem coordinating the OOC side of roleplay around her actions.
When Avanda grew stale and her story wrapped itself up, I decided to stretch my wings and not play it so safe, to try a character much more unlike myself. Casting around my stock of tried-and-discarded character concepts, I settled on Azhaar, an ironic counterpoint to the serene and contemplative draenei. Suffering a burden of rage, constantly driven to violence, attempting to solve every problem with her warhammer, a rogue templar disbarred from the Vindicators for sheer extravagant viciousness...she's a departure for me.
It took me some time to really get into Azhaar, but it was rewarding. Taking such risks is how we grow as writers and roleplayers, and I'm glad I did. Now, though, I'm almost beginning to regret it: I think she's making me a little crazy.
Azhaar's story was always meant to be one of wrestling with her inner demons and finding a source of peace, letting go of anger. During the Cataclysm era that made satisfying progress and provided some great RP. Then came the latest expansion, the story pushing players more and more into conflict between the factions with an undercurrent of the dangers of festering emotion embodied by the Sha. It's a story that could have been tailor-made for Azhaar, and suddenly RPing her has become a somewhat alarming experience.
Getting into the head of a character requires a measure of letting go of yourself. That is, as I noted above, a big part of the appeal. When that character's head is somewhat broken, you get into a very weird place. The blood elves have always been the Warcraft race for which I had the greatest interest and sympathy, hence making my previous main a sin'dorei. When Azhaar started loudly advocating dropping mana bombs on Silvermoon and the Sunwell and I caught myself thinking this was a pretty reasonable idea, it was a kick in the head.
I've been spending more time on alts lately, and even when on Azhaar have been doing OOC things like dailies and working on my Loremaster. Playing her in character is taking me to an increasingly dark place, one I'm not entirely sure I can control...but at the same time, I hate to wrench her onto another path; even if it is more comfortable to me, it would be untrue to the story, and I hate character derailment under any circumstances.
I'm interested in opinions and perspectives. What about you, Wyrmrest? Do you ever find your characters getting away from you, or getting too deeply in your mind? How do you address such things? Let's hear your point of view.