Mood is impossible to get behind, or to get clear about, or to get clear of. I am always surrounded by objects that matter in some specific way.
Mood is neither a feeling nor a set of objective movements. It is a unified style of activity in an appropriate situation. When one is afraid, one does not merely feel fearful, nor is fear merely the movement of cringing... fear is cringing in an appropriate context.
Mood is a primordial kind of being for dasein, in which dasein is disclosed to itself prior to all cognition and volition, and beyond their range of disclosure.
Mood is like the Niger River in Africa... no one knows its source, no one knows its outlet'only its reach is known.
A Mood is like the weather. It settles in and tends to perpetuate itself. For example, when I am annoyed, new events, even those which when I am joyful show up as challenging or amusing, show up as grounds for further annoyance.
A Mood is not a first-person, subjective state. Thus our cartesian tradition has forced us to conclude that it must then be some kind of third-person, objective behavior.
A Mood is not related to the psychical and is not itself an inner condition which then reaches forth in an enigmatical way and puts its mark on things and persons. It comes neither from 'outside' nor from 'inside' but arises out of being-in-the-world, as a way of such being.
A Mood is not a psychological experience in us. Rather it is something we are 'in'. We are 'in' a mood just as we are 'in' trouble, or 'in' a pinch.