If Two People Hate Each Other...

This is an interesting question indeed.

I got a girl I had been felt in love with, but she hated me so much, so I started thinking if she loved me in such a twisted way?

I guess I was wrong. Our era is not a good one, and people are totally illogical. Hence, there are no friends who hate each other.
Friends do not hate each other, they love each other.

I have acquired the position that a 'friend' is someone who
licks your boots in the hope of knifing you in the back later.

Or who, detests when you have success, out of envy,
detests when you have failure, out of spite,
and resents if you are an equal out of lack of identity.

Whereas an enemy is at least an honest reflection of their intent ;
is thus easier to predict, and thus less harmful.

Interesting replies but the question still stands from another angle: friends share phenomena, two people hating each other share the phenomenon of mutual hatred, thus they are friends.

If two people saw one girl, does it make them being two boyfriends of hers? I guess not. Sharing the experience of having the same phenomenon doesn't mean anything.

Now I face the power of your argument. Honestly speaking it is metaphysically powerful, except for one (or maybe several?) thing: of self-reference. Because we don't know about it until now.

Okay, why do I see your argument as a point one, and why I take it powerful? 

First of all, yes, sharing the same experience allow people to have friendship, and be truly close, especially when they're talking to each other.

Then, this argument is metaphysically good, because, let's say the experience of two people is the same as Ex and Ey, where x, y - are people that may be a, b, .... In this case Ea=Eb is the same as to say experience of a = experience of b. We can numerize them like this:

    E¹a=E¹b; E²a=/=E²b; E³a=E³c & E³b=E³c --> E³a=E³b...
    
And here we can face a very bright one metaphysical point that Leibniz had reached in a certain way.

Okay, we might ask whether this possible:

    Ex=Ex?

If you remember, a formal model of friendship is:

   Ex=Ey <--> 'x is a friend of y'

But what about to be a friend to yourself? It's mathematically to have a self-reference, but how can this be possible? No, it's impossible. We may get it from these speculations:

    [(E¹x=E¹y & E²x=E²y & ... & Eⁿx=Eⁿy) --> x=y] is false

And it must be obvious that this is impossible: totally same experience cannot be a friendship. So according by this logic we can just substitute the variables into the previous formula to get the answer: 

     [(E¹x=E¹x & E²x=E²x & ... & Eⁿx=Eⁿx) --> x=x] is false

So, if these speculations are correct, then one person cannot be a friend to his own, and two friends have to have some differences in their experience to be friends. 

If to continue this logic in this direction we can try to get some unexpectable results:

    (Ekx=Emy & k--> n & m-->n) <--> 'the fridnship is going to fail'
    E^kx=E^my & E^k/E^m=1/2 <--> 'the friendhip is going to be balanced'