"Enthusiasm is the electricity of life. How do you get it? You act enthusiastic until you make it a habit." - Gordon Parks
Have you ever heard someone say "fake it until you make it?" It sounds good, but often I have asked myself whether it is true or not. The quote above is actually quite similar to this, as it tells you to behave in a certain way until you feel that way.
In other words, even though you might not feel enthusiastic about a task, pretend like you are, tell yourself that you are, and behave like you are, and in the end, enthusiasm will take over, and you will actually have created a habit of enthusiasm.
It should also be mentioned that enthusiasm as described here is the electricity of life. It makes everything more interesting and fun, because it brings life into something dead. A light bulb without electricity is boring, but once it gets electricity, it brings light and warmth.
So, you need to have something to be enthusiastic about in life, and if you don't feel that way, start to act like you are enthusiastic until you actually feel that way.