One notable instance occurs early on in the film when Stitch is first introduced to Lilo's home. As mischievous as ever, he sneaks into the Pelekais' fridge and steals a can of soda. This scene portrays Stitch's impulsive nature and his desire for instant gratification, as he can't resist the temptation of the cold, refreshing drink.
Another memorable episode highlighting Stitch's affinity for soda takes place at Macki Macaw's restaurant in the episode “Phantasmo.” After an eventful day, Lilo and Stitch decide to treat themselves to a meal at the popular eatery. When they are served a pitcher of soda, Stitch eagerly waits for his turn to pour himself a glass. However, Pleakley, Lilo's alien friend, fails to pour any soda for Stitch. Frustrated, Stitch takes matters into his own hands and angrily drinks the remaining soda straight from the pitcher. This moment showcases Stitch's impatience and love for soda, as he is willing to go to great lengths to satisfy his craving.
In addition to these instances, there are other subtle references throughout the film that suggest Stitch's fondness for soda. For example, we see him enjoying a can of soda after stuffing Mr. Bubbles, a rival experiment, into a washing machine. This moment further emphasizes Stitch's mischievous nature and his penchant for finding joy in the simple pleasure of a fizzy drink.
It's worth noting that while Stitch's love for soda is depicted in the film, it is not explicitly stated why he enjoys it. However, one could speculate that the sweet, carbonated taste appeals to his alien palate, or perhaps it serves as a comforting reminder of his time on Earth with Lilo.