The boundary of a class probably lies within the heads of every single person, right? Are their interests at odds? If there is some objective idea of interests

The boundary of a class probably lies within the heads of every single person, right? Are their interests at odds? If there is some objective idea of interests, e.g. some ideal like "the American dream", some sense of a decent life and prosperity for normal people, then no. Our interests are shared (save for a few contrarians). However, most of us have our own moral principles that we believe should be used and not violated to achieve that interest. This is a real boundary that limits progress in one direction or another.