My life motto comes from a family movie called "Second Hand Lions". There's a scene where the Uncle gives the boy a segment of his "how to be a man" speech. I took the main summary line from that speech and simplified it to:
Believe in those things, because those are the things worth believing in.
The basic idea it that there are these lofty philosophical ideas: Justice, Honor, Love. These ideas are not physical things we can see, or consistent ideas we can all agree on. The premise is that we need to believe in these philosophical concepts, because they are things worth believing in, not because they are necessarily true. Here are some of the things I believe in:
1) Good actions bring good results
2) We are all interconnected
3) Humanity is on a path to progress