Ambitions. Apparently it seems to be what keeps a man going. Ambitions to fulfill, ambitions to complete. It can come in many forms, to being something in particular, to doing something, to just making ones life better.
Keep in check, for if your ambitions get out of your grasp, it'll jail you under your fears. What you wanted to be, the thing you wanted to do for good of everyone, turns against you, ruled by fear, ruled by evil ambitions.
For just as easily ambitions can be used for you as an advantage, it can be used against you as a disadvantage.