u/Glad-Complaint9778

From Suneo's Japanese accent, to the guy (who is Dutch btw) looking completely devastated, to the little "wakaru" Suneo adds, to his head shake and the "neeee", and to how Suneo's eyes move as Gian shakes him. And then Suneo adds the random "Oh no!" which is just hilarious for some reason, and then the "howdododo?".
It is also very funny how Suneo is so confident at the start, with his double-thubs-up, and then he loses all of that confidence when the guy doesn't understand him. His expression is quite like it was in the beginning of the 1987 movie Knights on Dinosaurs when he believed he was going crazy.

This is from the 1981 short film "What am I to Momotaro?" (well, that's one of the translations of that name).