Diogenes was an ancient Greek philosopher that was best known for mocking people. 

After observing an archer miss his target over and over again, Diogenes went and sat next to it, claiming that it was the safest place to sit. 

Another time, Diogenes saw the son of a prostitute throwing rocks at a crowd. He went up to the boy and whispered, "Careful son, don't hit your father." 

In another instance, when Diogenes asked for spare change, a man passing by said, "Yes, if you can persuade me." Diogenes replied back, "If I could have persuaded you, I would have persuaded you to hang yourself." 

Diogenes was also not a big fan of Socrates and Plato, going so far as  bringing food to their lectures and eating loudly to distract listeners. When Alexander the Great asked Diogenes why he was sifting through garbage, he responded, "I am looking for the bones of your father, but I cannot distinguish then from the bones of his slaves." 

Diogenes despised the superficiality and hypocrisy of humans and preferred the company of dogs. He was often described (in an unflattering way) as "Diogenes the dog," but he took it as a compliment, saying, "I am Diogenes the dog. I nuzzle the kind. I bark at the greedy, and I bite the scoundrels."