Boredom!

“Work spares us from three evils: boredom, vice, and need”
“Boredom: the desire for desires”
“Life swings like a pendulum backward and forward between pain and boredom”
“The cure for boredom is curiosity. There is no cure for curiosity.”
“The word aerobics comes from two Greek words: aero, meaning "ability to," and bics, meaning "withstand tremendous boredom”
“Uncertainty and mystery are energies of life. Don't let them scare you unduly, for they keep boredom at bay and spark creativity.”
“Procrastination avoids boredom; one never has the feeling that there is nothing important to do”
“In order to live free and happily, you must sacrifice boredom. It is not always an easy sacrifice.”