I secretly do bad things to my stepdad. Do you think that makes me a bad person?
What bad things have you been doing?
I make fun of him behind his back and avoid talking to him if I can.
It's fairly normal to feel some resentment or a lack of attachment to a step parent. It's important to be civil, though. Making fun of others is rude, and when that someone is in your household, it can sour the peacefulness and sanctuary of your home for everyone.
I don't care. It's none of your business.
You need to give him more of a chance. You might actually grow to like him. You can feel a little apprehensive but you need to work on growing as a person.