The Lorax/Tear Jerker

There were moments of sadness within The Lorax itself.

• From the TV special version, near the end, we hear the song the Once-ler sings to the boy and it brought this troper to near tears.
• From the film version itself, after the last tree is cut down, he is not only told by his mom that he was a big disappointment, but all the forest friends he had looked sadly at him (even the little bear himself). Still trying desperately to win them back after all that happens, he even offers the little bear a marshmallow, though the little tyke, with sadness in his eyes, only turns away. And then comes when the Lorax himself lifts himself up to the sky, leaving behind the stone that says "unless". Just the entire scene here...it brought tears in my eyes.
• This exchange, though sarcastic at first, makes you realize just how lonely the Once-ler's been...

Once-ler: Aww, you missed me.
Ted: What?
Once-ler: Well, you're already back. Clearly, you missed me. A little.(voice trembles slightly) Right?