Let’s say that you were madly in love with someone. And your mission was to tell the person that you love them. Here are two scenarios. One is you can take a week long train trip with the person, take your time. You’ll be in boring situations, beautiful scenery, everything. That’s a novel. The second scenario is she’s stepping on the train and you have three minutes. So you have to make all that decoration in three minutes. That’s a short story. You just have to shout it as she goes.