Whenever Sonic and Chip are together, and Chip tries to imitate Sonic's action pose. They are so cute together.
You can tell that Sonic was bothered by the fact that Amy didn't recognize him at first. Then he saves her and runs away before she can thank him. Who knew he really cared so much?
Add to that, Amy doesn't mind in the slightest that Sonic may be cursed to spend every night as a Werehog. She promises to stick by him regardless. It's true that nobody else seems to worry too much either, but you feel like they SHOULD notice, whereas with Amy it seems absolutely normal for her to not mind.
This troper was overwhelmed with an enormous sense of satisfaction that couldn't have been anything but this trope when he beat Sonic Unleashed and watched the ending. When Sonic pulls himself out of the ground after the Gaia Colossus threw him back up to the surface of the planet, he shakes his head, looks around, and sees Chip's unconscious body... but that's when the similarity to the intro ends; Chip's body fades away, leaving behind his necklace that happens to fit Sonic perfectly as a bracelet. As a heroic orchestral theme swells up, Chip says "I'll never forget you. I'll always be by your side... a part of the earth you tread." Sonic watches the sun rise, cracks a smile, and starts running along the cliffside as Endless Possibility starts up and Tails flies by, waving hi. Somehow, this simplistic Saturday-morning-cartoon-esque scene fit the tone of the game perfectly—there couldn't have been a better ending to the best 3D Sonic game in recent years.
An earlier one from the same game: After Chip (who is really Light Gaia) finally gets his memory back, he's about to fly off to finish fixing the planet by himself, only for Sonic (in Werehog form) to pull him right back. Sonic asks Chip where he's going, to which Chip responds that fixing the planet is his responsibility, and now that his memory's back, there's no reason to get Sonic involved in this. Sonic's response?
Sonic:"Do I need a reason to want to help out a friend?"