Boredom also plays a role in existentialist thought. Søren Kierkegaard and Friedrich Nietzsche were two of the first philosophers considered fundamental to the existentialist movement. Like Pascal, they were interested in people's quiet struggle with the apparent meaninglessness of life and the use of diversion to escape from boredom. Kierkegaard's Either/Or describes the rotation method, a method used by higher level aesthetes in order to avoid boredom. The method is an essential hedonistic aspect of the aesthetic way of life. For the aesthete, one constantly changes what one is doing in order to maximize the enjoyment and pleasure derived from each activity.
Some theories emphasize the role of the situation, some emphasize the role of the person, and some emphasize the interaction between situation and person in causing boredom. The present study examines these models by determining whether boredom propensity (person) and/or experimental condition (situation) independently or in interaction affected state boredom. The study also examined the relative contribution of behavioural activation and inhibition to state boredom. Boredom propensity and condition significantly and independently predicted state boredom, as did the interaction between behavioural inhibition and condition. Implications are discussed, including the possibility of two distinct causes of boredom.
One more key element of boredom is control. Boredom often occurs when you have little control over your situation. Waiting rooms, lectures, and airline gates are all places where you have little control over your situation. Normally, we react to unpleasant situations by changing the situation. If you don’t like a book you are reading, for example, you close it and do something else. Boredom happens when you are unable to change the situation.  
Acceptance Affection Amusement Anger Angst Anguish Annoyance Anticipation Anxiety Apathy Arousal Awe Boredom Confidence Contempt Contentment Courage Cruelty Curiosity Depression Desire Despair Disappointment Disgust Distrust Ecstasy Embarrassment Empathy Enthusiasm Envy Euphoria Fear Frustration Gratification Gratitude Greed Grief Guilt Happiness Hatred Hope Horror Hostility Humiliation Interest Jealousy Joy Kindness Loneliness Love Lust Outrage Panic Passion Pity Pleasure Pride Rage Regret Rejection Remorse Resentment Sadness Saudade Schadenfreude Self-confidence Self-pity Shame Shock Shyness Social connection Sorrow Suffering Surprise Trust Wonder Worry
Although it has not been widely studied, research on boredom suggests that boredom is a major factor impacting diverse areas of a person's life. People ranked low on a boredom-proneness scale were found to have better performance in a wide variety of aspects of their lives, including career, education, and autonomy.[30] Boredom can be a symptom of clinical depression. Boredom can be a form of learned helplessness, a phenomenon closely related to depression. Some philosophies of parenting propose that if children are raised in an environment devoid of stimuli, and are not allowed or encouraged to interact with their environment, they will fail to develop the mental capacities to do so.
“Boredom – the psychological state that we experience whenever we are uninterested in what we are currently doing – is one of the defining traits of humanity. Time is the psychological nemesis of humankind. Tedium, a fundamental angst of humankind, arises from human beings’ ability to perceive time and our attempts to derive meaning from our personal existence.”
When the antiproton was discovered … it sent a wave of ennui through the physics community. Not that its discovery was unimportant, but on the basis of Dirac's theory, everybody expected it. — Roger G. Newton, The Truth of Science, 1997 Chauncey and I were keen enough about our aesthetic solution to the ennui of war to try to proselytize others. He organized discussion groups with the crew; I took volunteers to visit landmarks … — Louis Auchincloss, "Atlantic War," in Authors at Sea, ed. Robert Shenk,  1997 The attendant outside was standing on tennis balls, exercising the soles of her feet, her body swaying back and forth with the ennui of jelly. — Edna O'Brien, New Yorker, 17 June 1991 Thus the days of life are consumed, one by one, without an object beyond the present moment; ever flying from the ennui of that, yet carrying it with us … — Thomas Jefferson, in a letter dated 7 Feb. 1787 Thomas Jefferson: Writings,  1984 the kind of ennui that comes from having too much time on one's hands and too little will to find something productive to do