I would say it's better summed up in the next episode
Kate: "I feel like such an idiot."
Angel: "A lot of that going around."
Kate: "I just couldn't... - My whole life has been about being a cop. If I'm not part of the force it's like nothing I do means anything."
Angel: "It doesn't."
Kate: "Doesn't what?"
Angel: "Mean anything. In the greater scheme or the big picture, nothing we do matters. There's no grand plan, no big win."
Kate: "You seem kind of chipper about that."
Angel: "Well, I guess I kinda - worked it out. If there is no great glorious end to all this, if - nothing we do matters, - then all that matters is what we do. 'cause that's all there is. What we do, now, today. - I fought for so long. For redemption, for a reward - finally just to beat the other guy, but... I never got it."
Kate: "And now you do?"
Angel: "Not all of it. All I wanna do is help. I wanna help because - I don't think people should suffer, as they do. Because, if there is no bigger meaning, then the smallest act of kindness - is the greatest thing in the world."
Which kinda goes back to what Angel said in a Season 3 ep of Buffy, 'Gingerbread'-
Buffy: How are you?
Angel: I'm alright. I think I'm better than you right now. I heard about this. People are talking. People are even talking to me.
Buffy: It's strange. People die in Sunnydale all the time. I've never seen anything like this.
Angel: They were children. Innocent. It makes a difference.
Buffy: And Mr. Sanderson from the bank had it coming? (sighs) My mom... said some things to me about being the Slayer. That it's fruitless. No fruit for Buffy.
Angel: She's wrong.
Buffy: Is she? Is Sunnydale any better than when I first came here? Okay, so I battle evil. But I don't really win. The bad keeps coming back and getting stronger. Like that kid in the story, the boy that stuck his finger in the duck.
Angel: Dike. It's another word for dam.
Buffy: Oh. Okay, that story makes a lot more sense now.
Angel: Buffy, you know, I'm still figuring things out. There's a lot I don't understand. But I do know it's important to keep fighting. I learned that from you.
Buffy: But we never...
Angel: We never win.
Buffy: Not completely.
Angel: We never will. That's not why we fight. We do it 'cause there's things worth fighting for. Those kids. Their parents.
And another one I like from 4.01 'Deep Down'
Angel: "What you did to me - was unbelievable, Connor. - But then I got stuck in a hell dimension by my girlfriend one time for a hundred years, so three months under the ocean actually gave me perspective. Kind of a M. C. Esher perspective - but I did get time to think. About us, about the world. - Nothing in the world is the way it ought to be. - It's harsh, and cruel. - But that's why there's us. Champions. It doesn't matter where we come from, what we've done or suffered, or even if we make a difference. We live as though the world was what it should be, to show it what it can be. - You're not a part of that yet. - I hope you will be. I love you, Connor... Now get out of my house."