One should guard against preaching to young people success in the customary form as the main aim in life. The most important motive for work in school and in life is pleasure in work, pleasure in its result, and the knowledge of the value of the result to the community.
Worry a little bit every day and in a lifetime you will lose a couple of years. If something is wrong, fix it if you can. But train yourself not to worry: Worry never fixes anything.