The highest levels of arousal and negative emotions. A person in a reactant boredom state has a strong motivation to escape his or her boring situation and avoid those responsible for it (such as teachers or a boss). Reflects significant restlessness and aggression. There are persistent thoughts about specific, “more highly valued alternative situations.”
The superfluous man (Russian: лишний человек, lishniy chelovek) is an 1840s and 1850s Russian literary concept derived from the Byronic hero.[42] It refers to an individual, perhaps talented and capable, who does not fit into social norms. In most cases, this person is born into wealth and privilege. Typical characteristics are disregard for social values, cynicism, and existential boredom; typical behaviors are gambling, drinking, smoking, sexual intrigues, and duels. He is often unempathetic and carelessly distresses others with his actions.
Boredom is similar to mental fatigue and is caused by repetition and lack of interest in the details of our tasks (such as tasks that require continuous attention, waiting at the airport, prisoners locked in cells). Any experience that is predictable and repetitive becomes boring. In general, too much of the same thing and too little stimulation can cause in its victim an absence of desire and a feeling of entrapment (Toohey, 2012).    

“When I have neither pleasure nor pain and have been breathing for a while the lukewarm insipid air of these so called good and tolerable days, I feel so bad in my childish soul that I smash my moldering lyre of thanksgiving in the face of the slumbering god of contentment and would rather feel the very devil burn in me than this warmth of a well-heated room. A wild longing for strong emotions and sensations seethes in me, a rage against this toneless, flat, normal and sterile life. I have a mad impulse to smash something, a warehouse, perhaps, or a cathedral, or myself, to commit outrages, to pull off the wigs of a few revered idols...”
"Meh" is an interjection used as an expression of indifference or boredom. It may also mean "be it as it may".[40] It is often regarded as a verbal shrug of the shoulders. The use of the term "meh" shows that the speaker is apathetic, uninterested, or indifferent to the question or subject at hand. It is occasionally used as an adjective, meaning something is mediocre or unremarkable.[41]
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.
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.  
In Experience Without Qualities: Boredom and Modernity, Elizabeth Goodstein traces the modern discourse on boredom through literary, philosophical, and sociological texts to find that as "a discursively articulated phenomenon...boredom is at once objective and subjective, emotion and intellectualization—not just a response to the modern world but also a historically constituted strategy for coping with its discontents."[3] In both conceptions, boredom has to do fundamentally with an experience of time and problems of meaning.
The bored antihero became prominent in early 20th century existentialist works such as Franz Kafka's The Metamorphosis (1915),[43] Jean-Paul Sartre's La Nausée (1938) (French for 'Nausea'),[44] and Albert Camus' L'Étranger (1942) (French for 'The Stranger').[45] The protagonist in these works is an indecisive central character who drifts through his life and is marked by ennui, angst, and alienation.[46]
“Time is quixotic because it can torment us. When we have insufficient stimulus to fill our lives, we resent the relentless quality of time, and we engage in activities designed to “kill time.” Time that passes slowly creates insufferable boredom; time that passes to quickly makes us aware of our accelerated death march. A person’s perspective on time depends mostly on what they are most afraid of, boredom or death.” 

Second, boredom typically occurs when people have trouble focusing their attention and they believe the reason for this difficulty is in the environment. When sitting in the airport, for example, there is probably a lot going on. There are people having conversations that you could listen to. You probably have something to read. There may be televisions showing the news. But, the stress of waiting for a delayed flight often makes it hard to concentrate, and so your mind jumps from one thing to another. You assume that this is caused by the environment, and so you feel boredom.
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.
In a learning environment, a common cause of boredom is lack of understanding; for instance, if one is not following or connecting to the material in a class or lecture, it will usually seem boring. However, the opposite can also be true; something that is too easily understood, simple or transparent, can also be boring. Boredom is often inversely related to learning, and in school it may be a sign that a student is not challenged enough, or too challenged. An activity that is predictable to the students is likely to bore them.[31]
“I don’t like to be bored, but without it I couldn’t escape from it. Creativity is the byproduct of escapism.⁣⁣ Inventiveness is the byproduct of laziness.⁣⁣ Productivity is the byproduct of your mom.⁣⁣ Lol. Anyways. ⁣⁣The bored do weird stuff to not be bored.⁣⁣ The lazy invent things like cars so they don’t have to ride horses. ⁣⁣Get bored to get busy.”

“I don’t like to be bored, but without it I couldn’t escape from it. Creativity is the byproduct of escapism.⁣⁣ Inventiveness is the byproduct of laziness.⁣⁣ Productivity is the byproduct of your mom.⁣⁣ Lol. Anyways. ⁣⁣The bored do weird stuff to not be bored.⁣⁣ The lazy invent things like cars so they don’t have to ride horses. ⁣⁣Get bored to get busy.”

“I asked myself whether a life devoid of any affection, of any goal, a life one fills with a thousand trifles intended to relieve its monotony, populated with human beings one seeks out in order not to be alone and whom one flees to avoid being bored by them, whether such a life isn't ridiculous, whether anything whatsoever wouldn't be preferable.”

The French loanword ennui comes from the very same Late Latin word that gave us annoy — inodiare ("to make loathsome"). We borrowed ennui several centuries after absorbing annoy into the language. Ennui deals more with boredom than irritation - and a somewhat specific sort of boredom at that. It generally refers to the feeling of jadedness that can result from living a life of too much ease. The poet Charles Lloyd described it well in his 1823 Stanzas to Ennui when he referred to that world-weary sensation as a "soul-destroying fiend" which visits with its "pale unrest / The chambers of the human breast / Where too much happiness hath fixed its home."