It's one thing to take your work seriously, but it's another altogether to take yourself seriously. Our work as Christians is certainly to be done with the utmost of care and devotion. But the minute we get too wrapped up in ourself is the minute we start to go in a wrong direction.
Here is a test. Call it a "self-awareness" quiz if you like. On a scale of 1 to 10, how much time do you spend thinking about your personal importance on the planet? In other words, do you view yourself as indispensable? Do you tend to think of yourself as God's gift to mankind?
The message of our culture is often, "It's all about you." And it is so easy to buy into it. By nature, we want to believe that it is all about us. But then the Bible comes along and presents a radical message about our nature and our sinfulness. That can be quite a jolt to our system, especially if we have been riding a wave of self-importance.