During those days, I read an article titled "Stop doing stuff you’re not passionate about", or something like that. I can't remember the exact title of the article, or even the writer! But I am so sure that the idea of the article is to stop doing things I am not passionate about and start doing the things I love.
I agreed with the author. Life is just to short just to waste it doing the things I don't love. I should waste my time to the things I wanted and loved. That way, I won't have any regrets in the future.

I guess the lesson here is that "If you’re not excited about what you do for a job - change it as soon as you can. Take that first step, whatever it is, towards doing something you love." :D