I'm going to make a joke about my italian culture
Is there a reason you want to do that?
Yeah, I don't really like italian people, they're rude and backstabbing.
You should be aware of your audience when telling jokes. And stereotyping is wrong even if it's about your own group. Not everyone has the same sense of humor.
Maybe I should make a joke about another culture then.
Some people might be offended by your joke. You should try to feel out a room before you preform the joke because you may be heckled or it could fall flat.