What is really special with Toy Story 4 is its screenplay and story. I cried two times during the film, during the montage of the first three films at the beginning of the film, and the goodbyes between Woody and his friends. It was really emotional, since we see Woody evolve through the film by having one simple objective, save Forky.
But as we see the difficulty of this task, we, the audience are in a really tense situation, in which we wonder, how will they save Forky from Gabby Gabby?, until we find out that Gabby Gabby (the villain) is actually a really depressed antique doll who just wants to be played with, so that is why she wants Woody's voice box. This conflict, in which either result will be really sad is what drives the story, and don't get me started on the Bo Peep storyline, which is a really well character driven story that will have you feeling for both Woody and Bo Peep.
The reason this movie really brings out the waterworks is because all of this problems and situations are resolved in very sweet non-predictable ways (which is good, because if it was predictable, we would still suffer from Woody sacrificing his voice box for Forky, but we still don't know what will Woody do, so that creates tension) that really impact fans of the franchise, because they have seen these characters, specially Woody and Buzz evolve since the first film, and now we see their conflicts resolved (remember, at the beginning of the movie, we clearly see Woody is suffering from not being played with that often) and seeing this conflicts resolved in an amazing Pixar way with an awesome screenplay, amazing animation, a killer score and a sweet story that really ends the arcs of this characters makes this film a masterpiece.
Also, the comedy is top knotch, Ducky and Bunny are a really fun comedic duo, and this balanced with the intense parts of the film, makes every little emotion stand out.
