Simple explanations

Why does the squeeky wheel get the grease? Because squeeky wheels are annoying, that's why.

The application of this concept to real life is that when you are living or working in an group, the best way to make your life easier to is pinpoint the people who can make the most trouble for you and make sure that you keep them happy. This is sometimes easier said than done, but it's a good exercise to at least know where potential problems lie.