Ambition. Because they don't think they could have an impact. Because they were always told ambition was dangerous. To get to the other side.

Questions to all these answers and more in the ambition tag!

Never confess to me that you are just as flawed as I am unless you can tell me what you plan to do about it. Afterward you will still have plenty of flaws left, but that’s not the point; the important thing is to do better, to keep moving ahead, to take one more step forward. Tsuyoku naritai!

-- Eliezer Yudkowsky