You see life from a new perspective once you understand that other people are not thinking of you anywhere near as much as you believed they were, and they only care about your usefulness to them. They disguise it with manners, compliments or religious niceties but deep down we're all selfish.
These are three rules that I try and always live my life by. Nothing bad ever comes from being silly with the people you love, being honest (even when it's a difficult thing to do) and being kind. What you put out into the Universe will always come back to you at some point in your life, so put more good out into the world, so goodness finds you when you need it most.