Why is this so important to you? (6.22)

Sam’s mental strength (1/…) : Love. 

he is willing to go through all of those memories, no hesitation, no holding back, only to get back to his brother, to not leave Dean alone out there. he could’ve chose many other reasons, ‘I know this wont be real’, ‘I want to save the world' but he chose what was in his heart. the thing that gives him strength, his love for his brother.