Depending on your definition. But taken literally, no, obviously not.

Regardless of your skill level, would you ever assume that you were playing a perfect (in the information theoretic sense) game of chess?

Whether chess or real life, all of us merely make the best choices we can given our skill and the information available to us. That includes imperfectly modeling the other agents in the world around us. In that sense, "being rational" means something like "deliberately analyzing the situation" and "more rational" means something like "a superior approach to analysis".