- [about Snoopy] What an independent dog. He comes and goes as he pleases, but I have to stay home and fix his supper.
- [numerous times in the movie] If I don't find out who Lila is, I'll go crazy!!
- [to an unhappy Charlie Brown] Listen, you can't let yourself get into a mood like this. I know you miss Snoopy. I miss him, too. But if you let yourself get into a mood, no one will want to be around you. No one likes a moody person, Chuck. Take it from me: I learned a long time ago that if you go around in a mood feeling sorry for yourself, you do it alone. And I mean alone, Chuck.
- [Charlie Brown picks up a rock from the beach, and throws it into the water]
- Linus: Nice going, Charlie Brown. It took that rock 4,000 years to get to shore, and now you've thrown it back.
- Charlie Brown: Everything I do makes me feel guilty.
- Charlie Brown: I'm depressed, Linus. I need an encouraging word to cheer me up.
- Linus: Happiness lies in our destiny like a cloudless sky before the storms of tomorrow destroy the dreams of yesterday and last week.
- Charlie Brown: I think that blanket is doing something to you.
- Charlie Brown: If I don't find out what happened to Snoop, I think I'll go out of my mind!
- Linus: If you'll calm down for a minute, Charlie Brown, I may able to conduct a little private investigation.
- Charlie Brown: Just what I need, a blanket-carrying Sherlock Holmes!
- Peppermint Patty: What do you think love is, Chuck?
- Charlie Brown: Well, years ago, my dad owned a black 1934 two-door sedan.
- Peppermint Patty: What's that got to do with love?
- Charlie Brown: Well, this is what he told me: there was this really cute girl, see? She used to go for rides with him in his car. And whenever he'd call for her, he would always hold open the car door for her. After she got in and he had closed the door, he'd walk around the back of the car to the driver's side, but before he could get there, she would reach over and press the button, locking him out. Then she'd just sit there and wrinkle her nose and grin at him. That's what I think love is.
- Peppermint Patty: [perplexed] Sometimes I wonder about you, Chuck.
- Linus: [about what he found out about Snoopy's past] You're not Snoopy's original owner.
- [Charlie Brown faints]
- Linus: Oh, good grief!
- [Charlie Brown gets back up]
- Linus: You bought Snoopy in the month of October, right? According to the records at the Daisy Hill Puppy Farm, Snoopy was bought by another family in August. This family had a little girl named Lila. Snoopy and Lila loved each other very much, but then they moved, and the family decided they just couldn't keep Snoopy so they returned him. [pause] You got a used dog, Charlie Brown.
- [Charlie Brown looks shocked... and faints again]