Why is there such heartless cruelty in this world?

All guys are like that or should I say most human beings. You cannot trust anybody in this world I tell ya. I am a very trustworthy guy but I keep my trust level to 80% to whoever I meet no matter how good, loving, caring they are. My family is the only one that gets my 100% trust. Other then that I would trust no one, that's what the world has become. Rumour spreading, back stabbing, disrespectful round oval we live on called the Earth.