1. As a snack, popcorn can increase the fun of watching movies. In the cinema, people usually want to enjoy some special experiences while watching movies, and popcorn is one of them. The aroma and taste of popcorn can provide a unique taste experience and make the movie-watching process more interesting.

2. Popcorn has a long history in film culture. Popcorn has long been regarded as a traditional snack in cinemas. This habit has been deeply rooted in people's hearts and has become a part of cinema culture. Eating popcorn can increase the sense of ceremony and make people feel more integrated into the atmosphere of the movie.

3. The production and sales of popcorn are also closely related to cinemas. Cinemas usually provide facilities to sell popcorn to increase extra income. This makes popcorn a part of the cinema and an expectation of going to the cinema.

Eating popcorn can also relieve tension. Some people may feel nervous or anxious when watching movies in the cinema. Eating popcorn can help distract attention and relieve this tension.

5. Popcorn is a relatively "environmentally friendly" snack. Compared with other snacks, popcorn doesn't leave much garbage, and it doesn't produce too much residue or other garbage except the bag containing popcorn, which makes it relatively popular in cinemas.

6. Popcorn is closely related to the cinema emotionally. Many couples, friends, family members or colleagues will choose to get together in the cinema, and popcorn often becomes a part of this kind of party. Eating popcorn can increase interaction and sharing, and make people enjoy this social experience more.

Generally speaking, it is a tradition and habit to eat popcorn while watching movies. It adds fun and ritual to the process of watching movies, and it is also closely related to the film culture.