I have been trying to understand the psychology of liking, for example a particular object(human or non-human). But I am unable to proceed with my experiments(I am just an amateur) because I myself discover that I like things at one moment and show no interest in them some other moment in time. Most of the things I see depend also on my mood. So it is this aspect called "mood" upon which I request the community members to throw some light upon.
What is the psychology of mood? Are there any books or mature/good reference materials to understand this phenomenon of mood better?