Negative speech will make you a negative person. Happy people are healthy, optimistic, and have more driving force to achieve. That's mere survival. Happiness is in your control. By not controlling it, you are slave to your emotions.
Happiness requires discipline, determination and hard work.
Don't wait for it to happen. Go out and create it. If you're busy patting yourself on the back for what you have achieved, you won't make an effort to do more. If you're constantly defending your opinions, you'll never be open to hear other people. If you are arrogant about your ideas, then you are limiting yourself.