Snoopy, Come Home1972

Peppermint Patty:
[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.