The scene where Lenny reveals why exactly he's still so hung up on Faith:
When I met Faith, she was just another runaway, giving twenty-dollar blowjobs to buy crank. Just another lost soul. But she had this voice... it was scary, like she could take all the hurt and rage of the entire world and lift it up to Heaven in one voice. I helped her. And I promised her that I'd always just be there, to protect her. See, it's not about what's in her head, it's what's in mine. I can't let go of the promise. It's like it's all I have left.
For added value, Lenny begins this by asking Mace whether she's ever been in love with someone who didn't return her feelings. Mace pointedly replies that yes, she has.
Max and Faith’s betrayal. Two people that Lenny cared about deeply (Max being someone he considered a close friend and Faith being his ex-girlfriend) both took Lenny’s love and trust and threw it right back in his face by trying to frame him for multiple murders. After a brutal fight, Lenny ends up killing Max in self-defense dropping him over a balcony. In the end, Lenny just looks at Faith with a mix of sadness and disgust before he walks away without saying a word while she sobs.
