[When Barry began speaking and explained that he had gone back to save his mother, Len was about to point out that he had done the same thing, but Barry continued. He bit his tongue and listened, frowning faintly. Mainly, he hears the pain and guilt that Barry feels - for going back and murdering his mother again after having saved her, and trying and failing to fix everything, but winding up making some people's lives worse.]

Okay, you fucked up. [He sighs and rubs Barry's back] You know the first thing I did when I went on the Waverider? I went back to my old house, and tried to change my own history so my father never got caught stealing the Maximillian Emerald. And you know what? If it had worked, and I caused a disaster by changing the timeline, I wouldn't have cared. Not one bit. Because unlike you, I'm a selfish bastard.

[He draws a breath and lets it out] Barry, the fact that you're so upset about this just proves what we all know - that you're the best kind of person. It's not bad to occasionally think about yourself. You're just a special person, so the mistakes happen in a bigger way. You wanted to save your family.