Boredom

Boredom was an emotion.

The Doctor frequently claimed that he had left Gallifrey because he was bored. (TV: The War Games, Voyage of the Damned, Heaven Sent) However, Davros believed that this was a lie. (TV: The Witch's Familiar) The Twelfth Doctor confessed it was a lie while inside his confession dial. (TV: Heaven Sent) The First and Fourth Doctors admitted that there several other "pressing reasons" at the time. (TV: Twice Upon a Time, Logopolis)

Shortly before his death and regeneration into the Twelfth Doctor, the Eleventh Doctor joked that as Daleks spoke very slowly, he would probably "die of boredom" before they finally shot him. (TV: The Time of the Doctor)

Things the Doctor found boring included the planet Calufrax, (TV: The Pirate Planet) studying Druidic lore, (TV: The Stones of Blood) the Vulgar End of Time, (AUDIO: The One Doctor) the two weeks he ran Taunton in the 18th century, (PROSE: The Highest Science) sitting watching the cubes all day (TV: The Power of Three) and Earth in 2105. (TV: The End of the World)

Ace called Perivale "the boredom capital of the universe". (TV: Survival)

Gilgamesh believed that danger staved off the boredom of life. He scoffed at Enkidu's claim that there were worse things in life than boredom. (PROSE: Timewyrm: Genesys)

Morella Wendigo claimed to be bored of Tamsin Drew within seconds. (AUDIO: Nevermore)

Jack Harkness thought that the Arcans were boring. (TV: Cyberwoman)

Joanna Harris, a vampire, said that she had not been bored since the invention of the Internet. (PROSE: Vampire Science)

Das, a Neanderthal, did not understand why humans hated boredom. (PROSE: Only Human)

The New Earth Republic was so successful that boredom was the only problem. (PROSE: Synthespians™)

Bram and Gregor Van Baalen told their amnesiac brother Tricky he was an android as a joke to relieve their boredom. (TV: Journey to the Centre of the TARDIS)