The best investment you can make is in yourself.
Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful.
It's probably as unlikely that you would nowadays become as rich and famous as Bill Gates, as it was unlikely in the17th century that you would accede to the ranks of the French aristocracy. But the point is, it doesn't feel that way. It's made to feel, by magazines and other media outlets, that if you've got energy, a few bright ideas about technology, a garage -- you, too, could start a major thing.