The dog "Mother Theresa" was played by two 6-month old Newfoundland puppies named Molly (who did most of the work) and Maeve (who performed the water scene). Director Gary David Goldberg adopted both puppies at the end of filming.
According to director Gary David Goldberg, he gave the script to John Cusack and encouraged him to change any of his character's dialogue to better suit him. Goldberg was surprised by Cusack's response, who later sent the director about 35 pages of new dialogue for his character.
While at the meat counter in the grocery store, the butcher announces that the special is whole fryers. "Two breasts, two thighs and a wing." Aside from the fact that a whole fryer has more parts, do they really mean only a wing? Are these mutant chickens?
When Bobby joins the group and they sing "Come On, Get Happy", Bobby starts playing the piano while they're singing, but the instrument he's playing on is actually an organ and not a piano.
When Sarah is surfing the internet, there are no cables connected to her iBook, so she should be using an airport wifi connection. But on the next scene, when we see a close up of the menu bar, the airport wifi icon shows the airport connection turned off.
Jake: You know, but I think your heart grows back bigger. You know? Once you get the shit beat out of you. And, um, the universe lets your heart expand that way, and I think that's the function of all this pain and heartache that you go through and you gotta go through that to come out to a better place and that's how I see it, anyway.
Carol: Hello! Don't worry, it's just me. I'm in the kitchen. I filled your freezer again. There's now enough meat to feed every guy who answered your ad and still...