Paralysis of the Will.
The unpleasant job that is put off is likely never to get done. This is because of the human tendency to forget unpleasant things.
But there is a more serious aspect to the putting off of disliked duties. An accumulation of unpleasantness may cause abulia, or paralysis of the will. Apprehension over delayed unpleasantness may so preoccupy one that other things cannot be done effectively.
Thus putting off an unpleasant task handicaps other work.
It also means that we do the unpleasant task many times in worry, instead of actually doing it once in fact. Dreading a task can be more tiring than doing it.
Put the jobs you dislike at the top of each day’s schedule. You will be pleasantly surprised to discover how much easier this makes the rest of your day’s work.
Don’t file unpleasant tasks away in a drawer labeled “For Future Attention.” Keep them right at your fingertips until they are finished.
~ Dr. Donald & Eleanor Laird, The Technique of Getting Things Done. (1947)