- When Mittens finally lets her past slip.
"No, Bolt. See, that's what they do. They act like they love you. They act like they'll be there forever. And then one day they pack up all their stuff and move away and take their love with them, and leave their declawed cat behind to fend for herself!"*shocked silence*"They leave her. Wondering... what she did wrong."
- Anyone that has worked in an animal shelter should start bawling about now.
- There's a Fridge Horror element to this as well (or Fridge Tear Jerk, if you prefer): Cats are often lost accidentally during a move, whether it's due to a feline freakout at all the upheaval, or just due to people running out of time to look for their wayward outdoor cat. So it's entirely possible that Mittens' family did love her very much and are just as heart-broken as she is at their separation, and she'll never know.
- Oh, but it gets better! A lot of pet owners are unaware at how declawing an animal isn't just painful, but makes it impossible for them to defend themselves. If we're to assume that this is what happened, it's the equivalent of accidentally blinding someone, then leaving without telling them.
- Bolt and Penny finding a way out of the burning building, only to discover that the vent is small enough for him, but not her. And there's no way Bolt is going to leave her behind. The look on poor Bolt's face when he thinks his beloved owner is dead.
"You're my good boy. I love you."
- Having finally accepted the world as he knew it was a lie, Bolt continues holding on to the one true thing he has left - the love of his person - only for the first thing he sees after reaching the studio to be Penny in rehearsal, hugging the studio's replacement Bolt. And he leaves just before he can see just how miserable she is without him.
- Penny trying to get Bolt to play with his squeaky carrot toy. It's a small sign that this lifestyle has stopped him from even knowing how to like a real dog. His replacement is later seen playing happily with it, showing that, while he's not as talented as Bolt, he's at least a normal dog.
- Oh, God, the bit where Penny's mom is searching through the crowd outside of the burning set.
- A Tears of Joy variation: Penny, stretched out on a gurney and nearly passed out from being trapped in a fire, sees her nearly-unconscious dog wagging his tail as they're loaded into the ambulance.
- Penny hearing and embracing Bolt's replacement. Her euphoria over being reunited with her good boy immediately dashed out the second she sees the trainer call him to her.
- Really, any scene in which Bolt whimpers or shows sadness is heartbreaking, especially for people who have beloved pets of their own.