You might wish for a "dislike" button on Facebook, but wishful thinking could get you tangled up with scam artists.
Security experts say if someone sends you something on Facebook, asking that you click on the "dislike" button, don't do it. It may read "I just got the dislike button, so now i can dislike all of your dumb posts LOL!!" It may also say, "Get the official dislike button". Both would be followed by a link. It's just another way for someone to get personal information.
Facebook says they may introduce a similar feature, but right now, "dislike" does not exist.