Do atheists believe in the existence of friendship?

[The Valkyrie]

Wait.

I thought we didn't believe in yellow?

You're thinking of the Green Lanterns

The movie?

I definitely don't believe in that.

[A. Secular Human]

Nope.  Atheists don't believe in friendship, dragonfruit, or the color orange.

Wait.

I thought we didn't believe in yellow?

 That was only until I got jaundice.

[Gawdzilla Sama]

"When Cthulhu gives you lemons, make lemonade."

[KerimF]

Sorry, soon after I wrote you, I somehow predicted your reaction.
I admit that I had to say it differently.

Now, let us forget about me. And imagine any human on earth instead of me. What could be that thing?

The question still doesn’t apply, as I’ve never tried to make friends with anyone. Friendship is more organic than that.

Nor do I feel the need to demonstrate my friendship to other people. That's nonsensical.

Boru

Okay, and I am sorry for wasting your time talking with you about something you are not interested in, in the first place.

[Astreja]

If two persons stand before you, please let me know how you could be sure that friendship exists in them or not. Thank you.

It's impossible to be 100% sure because one or both of them could be faking it, but someone's behaviour is the best guide to whether or not they consider the other person a friend.

[KerimF]

First, thank you all for taking the trouble to answer my first question by a big YES, though each of you did it by using his artistic talent

Now, it is time for the second question

If two persons stand before you, please let me know how you could be sure that friendship exists in them or not. Thank you.

Naturally, the third question will be based on how each of you will answer this second one

Friendship is the name we put on a series of behaviors and feelings demonstrated by humans toward each. And lack of other behaviors that one associates with not being friends.

Of course friendship exists, because we can see people demonstrating those behaviors toward each other.

If two people are standing before me, and they are demonstrating most or all of the behaviors we associate with friendship, are avoiding the behaviors we associate with not being friends, that is pretty good evidence that they are friends.

For example, if I see them help each other out, go to movies or concerts together, wish each other the best in life, become sad for each other if they are going through tough times, compliment each other, if one chooses the other to be her bridesmaid or best man at their wedding, etc, etc, etc, since that all is part of some of the collected behaviors we associate with friendship, as a third person observing them, I can be pretty sure they are friends.

Could I be wrong? Sure.

But the evidence is pretty compelling they are friends.

And yes, love, friendship, empathy, sympathy, dislike, etc, are all a result of brain function, and brain chemicals.

All you said about friendship is indeed true (and interesting). But I am afraid you missed the most important thing which, if accepted by both sides, their friendship becomes perfect. This thing has nothing to do with chemicals or feelings though almost all people look for it.
In fact, as we will see, the answer is known already by almost everyone here, for being obvious. So, I am surprised how no one mentioned it yet!

[arewethereyet]

So, friendship is god?

[KerimF]

So, friendship is god?

Please, we are in an atheist forum where God doesn't exist in the first place.

[The Valkyrie]

So, friendship is god?

Please, we are in an atheist forum where God doesn't exist in the first place.

Just like the real world.

[KerimF]

Please, we are in an atheist forum where God doesn't exist in the first place.

Just like the real world.

Why not?
But God is not the answer.