Why do we cry? Can you imagine life without tears? Not only do tears keep your eyes lubricated, they also contain a substance that kills certain bacteria so they can't infect your eyes. Give up your tears, and you'll lose this on-the-spot defense. Nobody wants to give up the flood of extra tears you produce when you get something physical or chemical in your eyes. Tears are very good at washing this irritating stuff out. Another thing you couldn't do without your tears is cry from joy, anger or sadness. Humans are the only animals that produce tears in response to emotions, and most people say a good cry makes them feel better. Many scientists, therefore, believe that crying somehow helps us cope with emotional situations.