Sinbad's realization about himself after he doesn't get the Book of Peace and Marina's impassioned defense of him. It's definitely a crossover with Tear Jerker when he decides to return to Syracuse to die instead of Proteus.
The exchange between Proteus and Sinbad is equal parts heartwarming and Tear Jerker
Sinbad: I bet you thought I wouldn't make it.
Proteus: I was beginning to wonder. *becomes worried* The Book?
Sinbad: I did my best, it wasn't enough.
Proteus: No. *look of realization* You came back anyway.
Sinbad: How could I do anything else, my friend?
The crew being in on Marina coming with them at the end of the movie. The big grins on their faces are absolutely adorable.
Watching Sinbad see Marina for the second time. Sinbad, the plunderer of the seven seas who would have a quip for every comment, is reduced to a speechless mess.
Sinbad's dog Spike. Just... Spike in general.
Proteus' is more or less a walking moment of these.
When he first hears Sinbad's voice, the look on his face is one of pure happiness that his friend is alive.
When Sinbad gets knocked overboard and dragged underwater by a giant sea monster, Proteus immediately jumps after him and only his crew 'physically restraining him' prevents him from going to his friends rescue. And he's clearly relieved when Sinbad turns up alive and well.
Proteus is clearly happy to see Sinbad at the ceremony later, easily falling back into their old friendship as if no time had passed or as if his friend hadn't tried to rob him earlier that day.
Proteus is the only one to believe Sinbad is innocent and willingly puts his life on the line for his friend. As in, Proteus will be executed if his friend doesn't succeed in an impossible quest or return for his own execution. And later, when given the chance to escape his dilemma, Proteus refuses. He just has that much faith in his friend.
After Sinbad's last minute rescue, Proteus immediately asks if his friend succeeded in his quest, knowing that him being here and having failed means the latter's death. The look on his face when Sinbad reveals that he failed, but came back anyway, is just heartbreaking.
In the end, his decision to let Marina go with Sinbad instead of marrying him as they were promised to do. He really is the noblest person in the entire film.