Tear Jerker / Paulie

• Little Marie running after her Dad's car screaming "Paulie! Fly back to me!" Especially since she's been trying to teach her friend to fly (he's afraid of heights) because she's foreseen this happening.
• It's just blown over when it happens, but when Ivy dies, it's not exactly uplifting either.
• And Marie and Paulie's reunion at the end.
  • "I loved you the first time I saw you, and I always will love you...Marie"
• Paulie getting his wings clipped (which he mistakenly believes to be permanent), especially this line...
  Paulie: They were taking away the one thing that made me different from them.
• Paulie discovering that the lab director has no intention of helping him find his owner. Punctuated by Paulie's outburst during a press release, which culminates in him screaming, "Liar!" over and over before attempting to escape, leading to the above-mentioned wing clipping scene.
• Paulie being kept in a dark basement, with minimal care and almost no human interaction, as a consequence for biting people out of anger after discovering he'd been lied to. The timeline of the film is somewhat vague (it takes place over roughly 20 years, but how long he spends in each location isn't specified), but it's heavily implied that he hasn't seen the sun in years, and there's actually a decent chance that it was for the majority of the 20-year span.