Misinterpreting people

It's silly of me, I know. I sometimes like to misinterpret something someone says. On purpose. I almost always feel guilty immediately afterwards, however I don't seem to be able to catch myself doing it in time to stop myself. It's especially embarrassing when it concerns someone who doesn't spot me doing it, like my grandmother. She might say something like: "I met this gay person, but he was perfectly fine." I might say: "Unlike all the other gay persons you have met in your life?" She goes: " No no, he was perfectly fine. Nice guy as well." I go "ouch" inside. Hope I'll be able to face you guys tonight now I know you know this.