From an essay well-known in technical circles:
Exploring the horizons of technology requires courage because research carries risks, even if we cannot always articulate them in advance…. [T]he very nature of research poses its own special risk. In research, we daily face the uncertainty of whether our chosen approach will succeed or fail. We steep ourselves in elusive, mysterious, and unnamed phenomena, and we struggle to unravel very complex puzzles, often making no visible progress for weeks or months, sometimes for years. We strive for simplicity and clarity in a cloudy and often baffling world. The special risk of research starts with the high probability that any particular attempt will fail and follows from the resulting experience of repeated failure. Research carries a special risk of discouragement.
Sutherland also as a nice bit about structured procrastination and how he deals with it:
For me, the urgent often takes the form of a crowded desk that must be cleared. All those letters to write, a timesheet to bring up to date, bills to pay, checkbook to balance, personal computer disk to back up, and a host of other easy little routine tasks are available to help me avoid the difficult big task at hand….
I escape from the local pressures by going far away in an airplane, or not so far to a quiet library, or even closer to the seclusion of my study, particularly early in the morning. The important thing about all these retreats for me is that I can cast aside the urgent problems; the phone won’t ring, the checkbook can’t be balanced, and I can focus on my larger tasks with a fresh mind.