I really liked the part just after Yusei, Jaden, and the Crimson Dragon arrived in Yugi's time. The look on Yugi's face as they drop him off after rescuing him was priceless. Not to mention that holler!
Little Yugi: WHOAAAAAAOH!
Bonus for Jaden and Yugi's expressions on the D-Wheel compared to Yusei's regular calm look on his face
The chattiness of Dark Magician and Dark Magician Girl, particularly compared to Junk Gardna, who's a robot, and Neos, who's mute. Given what they're facing, it borders on Casual Danger Dialogue at times.