In all seriousness I feel like the common answers I saw of Diogenes (because that was like, his entire shtick) or Socrates (because they killed him for being annoying) are probably better answers but saying its Trotsky on a leftist forum is way funnier.
I.F. Stone Breaks the Socrates Story: An old muckraker sheds fresh light on the 2,500-year-old mystery and reveals some Athenian political realities that Plato did his best to hide.
http://law2.umkc.edu/faculty/projects/ftrials/socrates/ifstoneinterview.html