Atheists, are we humans truly alone in the universe, or are you choosing to believe that because it feels good?

I believe it and it sure doesn't feel good.

To quote the late great Eric Idle of Monty Python. 

And pray that there's intelligent life somewhere up in space
Cause there's bugger-all down here on Earth

It is probably much more likely that life does exist else where in the universe than there is an omnipotent being over looking mans existence on earth.

Here is the answer atheism provides: "We see no compelling evidence that there are any gods".

If this answer does not satisfy the question, then the question is unrelated to atheism.

Just because no god exists, doesn't mean that life can't exist elsewhere in the universe. If anyone should believe that we are alone, it would be theists.

I will ADMIT the possibility that life exists elsewhere in the Universe.
  And I will believe it when sufficient convincing evidence has been presented.
I will also believe in Gods and Goddesses when sufficient convincing evidence has been presented.
   As someone wiser than I has said: An ALL-Knowing and ALL-Powerful GOD would KNOW exactly which INDIVIDUAL piece of evidence would convince EACH individual person of His/Her/Its/Their existence, and would have the POWER to produce each of those trillions of individual bits, rather than "inspire" people to write the Hindu Vedas, the Q'ran, the Torah, the New Testament, for us to argue, fight, and KILL each other about.

Said no Atheist that I know of...... There is always the possibility of life elsewhere.  Not as we know it, of course.  It is a lack of imagination and critical thinking skills that prompt a LOT of people to believe that this planet we live on was fine tuned for us.  Or the universe for that matter.  If the universe were fine tuned for anything it would be for the creation of black holes.  As for this planet, well,  only a very small percentage of it is capable of supporting human life.  The rest of it is hostile to humans.  99% of space is hostile to human life as well.  But life, in some form, could exist somewhere out there.  We just won't know until we stumble across it.  Fact......

There is absolutely no evidence of life outside Earth. You have to have great faith to believe that there is alien life on other planets.

I don't believe that. In November astronomers announced that they discovered unicorns living on planet 1,200 light years from Earth.

It’s not a matter of belief. I know that we are not alone on the Earth because there is always somebody for someone. The real aliens are on Earth because there are still species that have yet to be discovered by people.