Don’t be so negative

A Facebook engineer on why Facebook doesn’t have a dislike button:

Actions on Facebook tend to focus on positive social interactions. Like is the lightest-weight way to express positive sentiment. I don’t think adding a light-weight way to express negative sentiment would be that valuable. I know there are times when it’d make sense, like when a friend is having a rough day, or got into a car accident like my sister yesterday (she’s okay!). For these times, a nice comment from a friend goes a long way.