Have any of you

Yes and no. I had a friendship with three other girls similar to this. We laughed, cried, shared every single thought and feeling, but we only got together two or three times a year for a sleepover, and we never talked outside of that. I knew, though, that if I needed any one of them they would be there for me in a moment. I don't see how it's much different, except that we didn't see each other practically everyday. It's about the emotional support not the physical that's important. I think so anyway

It completely exists. The friendship these four characters have is completely real and I have experience it first hand.

No, but I've always wanted to! :/

I do. Though there's three of us in our cozy little trio. We were friends in college, saw each other every day, shared everything, cried, laughed, majored and minored in all the same subjects. However now we don't see each other that much anymore, different cities, different continents, but we stay in touch, and we have a day that we celebrate as our friendversary and no matter what we plan something on that day and make it happen!

English is not my first language, so please excuse any mistakes.