Can a boy and a girl just be "Friends" ?

The other day I discussed this subject with a very dear friend

She told me that she saw the movie "When Harry Met Sally"

and she started to wonder that whether a boy and a girl can truly be only friends?

In the beginning, I answered her immediately that of course that's possible

Later on she said that the movie has made her believe that it's just impossible

Because without any love involved in the relationship, it just cant last that long

And the kind of love is not as simple as we thought

After hearing a few examples, I started to think that whether she is right?

So I gave her an example to prove that she was wrong

I said that there is a guy who is really a close friend of mine

and I am so sure that I don't like him in that way, not at all

But I cant prove that he didn't once feel in that way so it cant count

I didn't want to agree with her about this idea

So I kept thinking whether I have an real good example to tell

In the end, I kinda gave up and start to believe that maybe she is right

When I looked back on the relationship I have been through 

I kinda found out that if the so-called love doesn't exist between a different gender,the relationship might just can't last that long

But we might find out it can't work to be together as a couple 

and then turn to be best friends instead

It is just an idea that "maybe" a boy and a girl cant be so close for so long

without having any special feeling in between

At least one of them might have a crush on the other at some point in the relationship, and later on found out it cant work so they stick with being friends

Though I kinda believe in this idea now, still I am eager to find one to break the rule

-Is there any exception? or You are the exception?