I tell people I was a music major in college simply because I looked at the course requirements and didn't see any math classes. That's only partially true... okay, only mostly true. I hated math growing up, particularly pre-calculus. The only single redeeming quality in pre-calculus was that we got to break out our TI-82's from time to time and plot graphs on our calculators. For that reason, and that reason alone, I remember asymptotes.

What's an asymptote? Simple: it's a straight line that is closely approached by a plane curve so that the perpendicular distance between them decreases toward zero as the distance from the origin increases to infinity.

See why I avoided math?

An asymptote describes a curved line that runs closer and closer to a straight line but which will never ever intersect the straight line.

Sanctification (the process of becoming more like Christ) is often just like an asymptote. Think of God's character as the straight line and our character as the curved line. When we first trust Christ, we seem to be becoming more and more like Christ in a hurry. But the longer our journey goes, the more we begin to realize that there's never a point at which the lines will intersect in this lifetime. Thus, as we mature, the change is not nearly as dramatic.  

Sometimes this is frustrating for believers who long for the good old days when they were changing like crazy. But as I talk to people who are further along in the sanctification process I've realized something: the more mature you get the more you stop caring as much about the degree of progress and focus instead on your nearness to the straight line.

Your focus changes. Rather than thinking about who you used to be, the focus becomes who you will be. So even though change is less dramatic, it's sure and steady, approaching the straight line more and more every day.