The issue, Shakespeare argues, isn't ambition itself, but the way Macbeth allows himself to be controlled by it. We know this because other characters, like Banquo and Malcolm, show ambition but know how to restrain themselves. They can judge the situation and recognise when it's best not to listen to their desires for the good of themselves, their loved ones, and the country they serve. Macbeth, on the other hand, is oblivious to morality and natural order.