I could spend thousands of words writing on this simple topic, but I'm going in for the kill, short and sweet.
Law #1: Have fun.
Life is ultimately about enjoyment. Being depressed or sad or angry are pretty shitty ways to spend your time. Stress and anxiety are also pretty heavy fun-killers too.
You have to ask yourself, in all things you do, "am I having fun?" You might even be brazen enough to ask "how can I have more fun?"
I spent a great deal of time (two years) doing something that I thought would benefit me. Practically, yes it did, but emotionally I was not enjoying my experience.
Those learning "Game" might be familiar with this. Moving outside of your social-comfort-zone is one of the most grueling tasks for a man to do -- but that's only because we perceive it to be a grueling task. Why not have fun with it? The problem is that many men see Game as work and something they have to do like homework or studying for an upcoming test. If you can learn to have fun with something, you will rule it.
Even when something is happening that is particularly shitty, you could still enjoy it. Enjoyment is half action/half mindset. You could be fucking the most beautiful girl you ever met but be unhappy about it. You could have just broken a bone and start laughing at how funny it is.
So we have a formula. The formula is A+B=Fun where A is actions in life (those you chose and those that happen), and B is your mental perspective of A.
I want you to understand that "unhappiness" and "non-enjoyment" (possible inputs of B in the formula) are mostly an issue of non-acceptance. If you completely accept whatever has occurred to you, there is no resistance and therefore no negative reaction to the situation at hand.
"Oh well, I broke my hand."
"Oh well, I made one million dollars."
"Oh well, I got mugged."
"Oh well, I got a raise today."
All these situations have been accepted. Notice how the reaction to every incident is the same. Do not resist the resistant and you will be stalwart in mood. I read a book recently called "Zen and the Art of Happiness" that said "Everything that happens to you is the best possible thing that can happen to you." While this might sound cheesy or insane, this idea will keep your spirits up. Always ask "how will this benefit me?"
Everyone of us has incidents we are not proud of; Incidents that we shunned at the time that brought us despair, embarrassment, shame, or any of the myriad of negative feelings. These experiences ultimately shape you and make you who you are. Do not deny that they have contributed to your life.
Yes, some things are fucked up like child sexual abuse, but even then as an adult that person can accept it happened and move on with their life. Dwelling on the past and worrying about the future have never accomplished anything. Ever.
Note: Feel free to enjoy positive experiences fully while they come. If you get a million dollars or a raise, go ahead and pop some champagne. Remember, have fun.
This post started simple and I vomited stuff about acceptance and living in the Now. To read more about these concepts, check out the book "The Power of Now" by Eckhart Tolle.