Take a look at your list of things to do.
Is there anything on it that has been carried over from yesterday?
How about the day before?
Is there anything on your list that has been there for a week?
If you postpone something and then forget about it, then the next time you see it, you might decide to put it back on your list; but no real damage will have been done to you psychologically.
If, however, you simply transfer the same thing to your new to do list, day after day, week after week, then no matter how minor it may seem to do that, the challenge to complete that task will grow in your mind.
It will seem to get bigger because by putting it off, you're training it to believe that the task is too complicated or too time consuming to do now.
This is what I call the psychological effect of failing to do K.
We talk about doing A, B, C, D, and E, or X, Y, and Z, but when was the last time you heard someone tell you that things could get serious if you didn't do K?
There's nothing special about the letter K, either as a letter of the alphabet or as a variable in an abstract problem. It's innocuous, in fact. What makes it significant is your behavior - that daily reminder that it's something that you ought to do, but keep putting off.
For some reason, it's important enough to put on your list, but not enough to do anything about it.
When you do this repeatedly, however, you also decrease your confidence in your ability to do it.
In the end, it occupies your thoughts, both at work and at leisure, and it leaves you too afraid to tackle what now seems to be an insurmountable challenge.
Today, pick that one thing that you have been postponing since forever and do it.