It's important because if you don't take the time to know them, you will never really know what they are like. You shouldn't judge someone by how they look. Just like the saying, you shouldn't just a book by a cover.
It is important because your first reaction might be wrong. You shouldn't judge a book by its cover - because there may be a lot more underneath that you are not aware of. Just talking to a person once or twice is not enough for you to base your complete opinion about them - getting to know a person takes time, and so does forming your opinion when it comes to them.
