pissface

Someone (esp. on an Internet 'forum') who is actively negative, and sees the bad in everything. This doesn't necessarily reflect their public persona, but rather takes advantage of the faceless nature of the Internet to rant and rave at strangers without recourse. Similar to a troll, but not as antagonistic, pissfaces can also be called miserablists, pessimists or Grumpy Old Men. They are often characterised by taking jocular comments at face value, finding offence where none was intended, and purveying a general attitude of negativity. The term comes from the (supposed) 'sour' qualities of urine.