Character mistake: After Cory and Topanga have their argument in front of everyone, Cory remarks to Shawn that it's their first fight ever. Cory and Topanga had several fights in the show prior to this. (00:12:50)
Continuity mistake: When Cory is lying on the couch during his argument with Topanga, the pink pillow is under his right shoulder. A few shots later, it is suddenly under his neck. (00:17:00)
Chosen answer: In the present day, with the United States abiding by more stricter school health laws, for the most part this wouldn't be in school cafeterias as many cannot even have carbonated beverage machines now. However, in the 90s when the show takes place, it wasn't unheard of for there to be coffee machines in the cafeteria of small schools where the teachers eat with the students as we see them do often in the show. The idea being that the cafeteria was small enough so a teacher or hall monitor could catch a student before they could drink the coffee.