An ISTP's "demure" nature will make them the targets of asinine bullying. Train at the Cobra-Kai dojo and kick the fuckers in the head.
+1 to the above. Gradeschool Survival is a matter of prison rules. Kick a bully's ass, or become someone's bitch. You go from calm and collected one second to an asskicking fury and back again once your point has been made, and people will back the fuck off. Just remember, the majority of bullies you'll run into are pathetic lumps of crap with a knack for aggressive posturing. -Tempest09