Life is never easy to any soul. Everyone have their own story, and their own problems. To us they are the biggest in this planet, while to other it may look silly. Life makes us want to quit, to give up but at the same time it gives us a reason to live on and love more. We get to find a purpose.
To Derek, life was never smooth, but he believed it's just his life and failed to see the life of other's. To Taaliyah everyone was struggling in their own way but she only cared about Derek and get depressed about hers later. She let Derek consume all her time. But the two were not willing to surrender to the fate.
To Derek, he realized there are no one he can consider close if not Taaliyah and everyone have the right to choose and make decisions. Especially after the divorce that happened between his parents. Amy became his greatest life lesson.