The context of the quote is also worth noting. Jim Rohn, the author of the quote, is a self-help guru. His quote is for those trying to improve their personal and business life. If you are trying to lose weight, then making friends with 5 healthy, active people will help towards your goal, while making friends with 5 obese people who choose to eat junk will hinder your goal. In this context, I think it's useful. As ageless wisdom like something from the Tao Te Ching... it falls a bit short.