Part of what I work on is self-expression, which is neither a modern idea nor an ancient idea but something in between. It was actually in the Renaissance that as far as we know the very first person wrote the words I expressed myself and that was Angelo Poliziano. He was a humanist scholar and a poet and he was involved in this enormous debate about whether you should imitate Cicero or some other ancient writer when writing your own Latin prose.
And he said you know what? I don't want to express Cicero; I want to express myself. So when you open yourself up to the ways in which people in other times in places framed a problem, you may find yourself reconceptualizing what the problem itself is and how you might go about solving it.
And I think that's what humanists do. We really question the very metaphors by which we understand who we are, where we are on our planet and our societies, and it self-expression really is about connecting yourself to the rest of the world and the people in it.