Alien theories

Are we alone in the universe? This question boders humanity for a long time. We all want to know if there is "somebody" out there but the same time are scared to know. When we look in the sky, do we look at shining stars or other civilizations far far away asking themselves the same question? I personally think we are not alone and here are few theories of mine about why aliens have not contacted with us yet:
1. None of the civilazations from outer space are advanced enough to contact somebody from other planets (either cannot travel to other planets or have not figured out how talk with species from space).
2.Other civilaztions don't want to contact with us because they don't see benefit from this meeting or know that our planet is not ready for this kind of milestone in it's existance. I'm pretty sure majority of our population would freak out about news like that. Maybe they know we would start a war with them and bring nothing good.
3.We haven't contacted with anybody because we are too far from everybody. Placement of the earth is just unlucky. Or maybe lucky, who knows.
4. Aliens have contacted with us but special authorities have kept that secret away from us because they know we are not ready for this kind of news.
5. They did contacted us but a long time ago and no we have no records or proof about it.