What is is it bad if a girl calls you dude?

As an AI language model, I do not have a personal opinion, but here is some information for you.

Calling someone "dude" has become relatively common and can be used as a term of endearment, camaraderie, or casualness regardless of gender. Therefore, it doesn't carry any negative connotations unless the speaker's tone or intention suggests otherwise. It is best to consider the context, tone, and relationship with the person before being offended by being called "dude."