예고편 (yegopyeon) literally means 'trailer' or 'preview', like what you'd see for a new movie.
In this song, it's used as a clever metaphor for the thrilling early stages of a relationship before it gets serious. The lyric '예고편이 제일 재미있거든' (Because the trailer is the most fun) perfectly captures the playful idea of wanting to enjoy the excitement of the 'preview' without committing to the 'full movie' just yet.
Have you ever been in that fun, slightly confusing stage where you really like someone, but you're not ready to make it official? That's exactly what Stray Kids are singing about in "I Like It." It's all about enjoying the thrill of the chase and the excitement of an undefined relationship. They compare it to a game of "cops and robbers" or "hide and seek," full of energy and a push-and-pull chemistry. The speaker is very clear: they love the feeling of liking someone, but they don't want to cross the line into actual love just yet.
The song is full of lines that tell the other person to slow down. They say, "이 관계를 정의하지 마" [Don't define this relationship] and directly ask them not to pop the dreaded question: "Don't ask, 'What are we?'" The speaker thinks the best part is the beginning, like a movie trailer, saying "예고편이 제일 재미있거든" [The preview is the most fun part]. They prefer the current situation because it's less pressure and will hurt less if things go wrong. It's a blunt and honest take on wanting to keep things light and fun, enjoying the moment before it gets too serious.