Most of the gankers fall into one of these categories:
No Lifers - Generally unpopular irL so feel the need to boost their confidence by showing superiority online.
Bullies - These people have no respect for anyone because they never felt loved by the ones they needed irL.
Fails - Generally players that can't 1v1 other players their own level and gear, so they kill lower levels to compensate for their lack thereof.
Vigilante/Avengers - Got ganked in the past and doing the same, thinking it'll solve the problem, but only adds to the problem.
There are many other categories, but these are my top lists. I'm on Horde side so if you ever need help and I'm online, message me on Auryia or Lyllac. Enjoy the game, don't make it unpleasant for others because you had a short unpleasant experience. You die, you resurrect, you live again. Keep treading.