Do you think that just because you have a good relationship, you can joke around casually? True intimacy is not based on "casualness," but on "tact." All jokes that make people uncomfortable inherently carry contempt or neglect; whereas someone who truly values you will instinctively avoid your sensitivities and boundaries. So-called jokes should not be wrapped in harm, but built on understanding and respect. What makes you upset is never the joke itself, but the other person's failure to consider your feelings. A joke that makes you uncomfortable is not a joke; it's a crossing of boundaries in the relationship.