I've seen this term thrown around loosely and in different contexts. All-Time Favorite dictates that only one can exist at a time. However, I've seen frequent mentions to ATFs, which better translates to all your favorites. What is the commonly defined relationship between a hobbyist and a so-called ATF? What are the rules, the guidelines, the proper etiquette to behave by? Is it solely a one-sided affair, or does it have to be mutually agreed upon? Do providers have ATF clients? How do you get in such good graces with a provider? How far above and beyond do you have to go to secure that bond?
Sometimes I'll read someone talking on the forums or in reviews about how their "ATF" lets them do this or that, gives them perks or benefits, extended time, freebies, etc. That sounds like a really special connection. I suppose the proper question then might be to inquire how one obtains such a platinum-standard ATF. I've had good experiences and I've had bad experiences. Logic and common sense would have me believe that my 'best experience ever' would be my ATF provider. However if that isn't a mutual decision, it doesn't really count.
I've protracted this question long enough. All my deductive reasoning leads me to assume that I don't currently have an ATF. By which I mean that none of the providers I've seen seem to care about me outside of our session time. What are the proper practices of ATFs? Are they your friends in real life or just pretend? Someone you can talk to outside of the hobby? Are they there to comfort you and make you feel good (and vice versa)? Do they go above and beyond a session to do whatever they can to please you? Or is it simply a title for your favorite provider. Please enlighten me, because if I have to hear one more hobbyist gloat about his 'special relationship' with his ATF, I'm going to lose my shit.
TL;DR: What is the proper definition of an ATF?