Separate your problems. If you need to keep your nasty thoughts about Joe private, find ways to keep things private: an easy-ish way is to type your thoughts and put them on an encrypted flash drive. Or write them as emails to yourself in an email account set aside for that purpose. Joe's not going to hack into your computer (I hope, and if he is you should be calling the police not reading LessWrong), so security-through-obscurity is more than enough.