There are too many people in the canteen.
Everyone usually goes to the canteen to eat after class, because everyone finishes class at the same time, and the canteen will be crowded. You have to wait in line to cook, and you may not have a seat, especially when several students go to eat together, so you can't sit together. In case the teacher drags on a little longer, there will be no food. On the other hand, the small shop outside the school is spacious and there are not many people, so everyone can sit down and chat.
Tired of eating the food in the canteen.
The biggest reason is that students are tired of eating in the canteen. When we eat at home, we will find countless ways to change the pattern of three meals a day. However, the food in the school canteen is relatively simple. Even if there are several canteens, they will be finished after eating for a while. In other words, you need to choose three meals a day in the school cafeteria. This can be done in a year or two, but how to spend three or four years? When I was a freshman, I ate in the canteen all year. As a result, I really threw up in the school cafeteria, and then I went out to eat. There are many kinds of snacks to choose from outside, and the pot rice in the canteen can't satisfy all kinds of college students. In order to meet personal taste needs, we can only eat snacks outside.
Dish reason
School meals are mostly cauldron dishes, and some packages will be fast food packages (I have seen them myself), but the taste can only be said to be passable, not particularly delicious (but some stalls are delicious). The snacks outside are all made on the spot. They are very spicy and delicious. What's more, many snacks belong to junk food, which is oily and contains a lot of polysaccharides. Such food is certainly delicious, but it is not recommended to eat more.
economic conditions
Now, some college students have some money in their hands. If you have no time to eat out because you have a class, eat two meals in the cafeteria. The food in the canteen is not delicious, but it is relatively cheap. The chef in the canteen does not consider whether the food is delicious or not when cooking, and the students will not come. But students who have money and time will choose snacks outside school.