Keep all your promises, don't take what doesn't belong to you, and always look after those less fortunate than yourself, and you'll do well in the world.

What Walter thinks is that people are like rivers. We never stay in the same place but jest keep flowing along, learning new stuff and picking up new experiences and changing all the time. So today’s you isn’t the same as yesterday’s you and won’t be the same as tomorrow’s you. But Walter also thinks that there’s a real perfect you that you’re always trying to get to, and the better you are at living your life, the closer you come to it.