GFE, by it's very name, denotes fakery.   A real girlfriend, whom you feel tremendous passion toward, and she toward you, will not be looking at you with counterfeit eyes.  If you know how to ring her bell her moans will not be fake.

But a provider fakes everything.  Your eyes mean nothing to her and it takes someone pretty special to ring her bell.  So if she fakes her way through it with moans or contrived passion, and you don't buy her act, then she is simply not the kind of faker that turns you on.  Some guys need that shit to make them at least believe for an hour that what they are getting is real.