Okay. Let's be blunt. Enthusiasm isn't always lauded. In fact, many times folks want to put it down, as thought an adult being enthusiastic is indecent, or that the enthusiastic person will use up all the available energy and there won't be any left for others.
Here, then, is the secret to enthusiasm, so that it will spread like a virus and then we'll all have it.
What makes you passionate?
What gets you ranting?
When you have the time, what do you like to do? Not the socially-acceptable answer, but the real truth?
What common themes occur in the answer to the previous question?
The more that you understand these things, the more enthusiastic you become about them. Don't be afraid to follow your passion. No matter what people say, being enthusiastic is the secret to happiness.