Today I felt first hand how short life actually is. Treasure every moment. If you get angry at someone you love, stop for a couple of seconds - think, and try to show love - not anger. If you are too busy to spend time with them - make time. If someone is really important to you, do not take them for granted, or have the misconception that life is static.
The sad news is - even if you follow all these suggestions, it won't make any difference to how you feel. Life is unfair.