It’s a complex and summarized mixture of everything going on in our body at a particular time (as to orient us), and it varies from one instance to another.
Arthur Schopenhauer: The Two Things That Stop Us From Being Happy
Zat Rana

An emotion is also part non conscious cognition, including our subjective concepts, context and memories. To resolve this dichotomy between thoughts and emotions, I have proposed the following equation: (conscious) emotion = (non conscious) affect + cognition. Affect of course is your combination of valence (pleasure/displeasure), arousal and motivational intensity. When you frame the discussion in terms of the constructivist paradigm you see that pain simply = displeasure and boredom is displeasure + low arousal and low motivational intensity.