Important? Urgent?

Yesterday I learn Time Management the first time:

To-Do things should be classified as 4 categories:
1, Urgent and Important: Things that you are responsible for, and have near dead-line.
For example, filling out tax return in 2 weeks, or writing reports by Friday.
Things in this category must be dealing with immediately with all your attention.

2, Important but not Urgent: Self-improvement, or things that you have plenty time to do.
For example, submitting a paper in 6 month, or reading "A beautyful Math".
These things are important because you are responsible for it and it can become "Urgent and Important" if you keep delaying it. It is important to your long term development. So we should setup regular time everyday to work on them.

I always have trouble with things in this category. If it is interesting, I indulge myself in doing it full-time, because I have perfect alibi: IT IS IMPORTANT! So I do this instead of the "Urgent and Important" things, when I have deadline to meet. That makes me frustrated in failing deadlines and questioning my ability. If it is not interesting, I delay it until I am cornered. That also leads to frustration.
Solution: Setup one hour everyday to read books.

3, Urgent but not Important. That is not really your job. Mike might ask you for help, or you think of an interesting topic to put into blog. We should do it immediately and finish it as soon as possible.

4, Not Urgent, and Not Important either. Like, checking emails, visiting BBS. Do it when you don't have anything better to do.

This is very basic strategy in dealing with to-do list: Priority Matrix. I can't understand how I survived these years without this knowledge.