Inertia

The Medrash Tanchuma says that the first test Avrohom faced, leaving Charan, was as difficult as the last one, the Akeida. That's why both tests begin with the words "Lech Licha". This Medrash is hard to understand because we know that each test was increasingly difficult, like a mountain that Avrohom needed to climb to get to the top.

Rav Elyashiv says that most people fail in life due to inertia. They can't bring themselves to take the first difficult step. The gemara in Succah (52b) says that when Hashem will finally kill the Yetzer Hara, the Tzaddikim will look at the Yetzer Hara and shed tears about the impossibility of overcoming a huge mountain, while the Resha'im will stand by and cry, lamenting how they were unable to overcome a hairsbreadth. What does the Yetzer Hara actually look like, a mountain or a hairsbreadth?

Rav Elyashiv says that both are true. At first the Yetzer Hara is weak and flimsy. The difficulty in overcoming him, is that you need to get up and fight, which is a huge hurdle. As you move down the path he gets bigger and stronger. The Resha'im who could never get past the first step, see the weak Yetzer Hara, while the tzaddikim see the mountain. Both are equally challenging in their own way.

Although the first test of Avrohom to leave to a land of promise was not as challenging, the mere fact that it was the beginning of his journey made it most difficult. No less than the last test which he faced already battle hardened, but a test so great it was like no other.
 http://www.revach.net/parshas-hashavua/quick-vort/Parshas-Lech-Licha-Rav-Elyashiv-Avrohoms-First-Baby-Step/2922