I keep my rules simple. If someone's nice to me, they're worth
  my time. If they're not nice but have potential, they're worth
  my time. If they're a hopeless case, then they're not worth my
  time. Takes a long time for me to consider someone a hopeless
  case, but there's about a dozen or so ppl in the world that fit
  that. But I take ppl as individuals and I'm slow to cut off. But
  when I do, I have to be absolutely certain.