Its a defense mechanism... Dont continue making jokes to try and be thier friends... just be nice and courteous towards them when applicable- demonstrate that you don't mean any harm (its not like you are trying to get them fired or anything). It almost sounds like you are teetering on the edge of the "trying to hard ot fit in" crowd. Let it come naturally rather than force it. It is just a different philosophy on work between you and them. Try and find a crowd at work that subscribes to your same philosophy.