“I think people have asked about the dislike button for many years. Today is a special day because today is the day I can say we’re working on it and shipping it,” Zuckerberg said during a Q&A at Facebook’s headquarters.
Zuckerberg said that the social network didn’t immediately design way because it didn’t want it to become a Reddit-style system of upvoting and downvoting.
I can see why Facebook has taken it’s time to release the dislike feature. Sure it looks easy and sounds easy to make. But then you have to be careful how people use the dislike button and feel about it. If I posted a picture of something I like, I don’t want to see friends disliking the photo. Then you have the post where maybe something terrible happen in some part of the world, you don’t want to like it. So Facebook has to think careful when design a dislike feature.