The root of Menashe's name is "forget" while the root of Ephraim's name is "dust." 

The Shem Yeshmuel says that Ephraim represents the physical world while Menashe "forgets it"/tries avoiding it. 

What made Yosef into that Tzadik that we know him as was his ability and greatness to run away from Potiphar's wife. Yaakov on the other hand, represents bringing the physical and spiritual together as one. 

On Friday night we say the word "שמור" during Kiddush, while on Shabbas day we say the word "זכור." The difference between the two is שמור represents guarding and protecting yourself from work during the week and זכור represents remembering and actively doing good to make Shabbas special. 

To tie this all together-- Yaakov accepted the sin in the world and knew what was going to happen, and therefore realized that the one who needs the Bracha is the one who is going to elevate the spirituality that exists within this world, despite the distractions that exists. Yosef was the opposite. That's why he gave Ephraim the blessing with the upper (right) hand. 

We live in a world that's filled with sin and distractions, but don't let that be the reason that you give in. We are all blessed to bring out the light within the darkness.