Knowledge is an endless infinite-leveled mountain. Each step, giant or small, you take towards the top is expanding your skyline, which is great. But those same steps seems to make the tip of the mountain higher. Looks like Uncle Socrates was right, and that the luckiest (or wisest) of us can only know that one thing.
The crowning touch: when you go back to the lowest level and explain to others how great it is to come up, you are nothing but a jerk (or maybe it's just me).