Emotion, especially strong emotions, will tend to distract and bias your thinking. This is "obvious from everyday experience" which is why you don't try to do any difficult thinking while in the grip of strong emotions, at least not if you're rational. But this does not make them "antithetical".

Harry Browne, in "How I Found Freedom in an Unfree World", suggested the purpose of developing a personal morality is to have rules to guide your actions when you are too emotionally engaged to think rationally. You think out the appropriate responses to various situations and problems rationally, then use these responses as rules to guide your behavior when you don't have time or are too distracted to think rationally.