i use Chrysler's vin number price classification (second digit) format to rate "friends"
L : Low: an L code is an acquaintance someone i dont really know and wont put any time, money, or effort into getting to know them....just let things happen naturally.
M : Med: an M is a person of interest, someone i want to know more about....i will put time, low budget, and moderate effort to get to know OR someone that i already know moderate info about and so far like what i see and know about the person
H: High: an H code is someone i really like, and i am willing to do a lot for this person. time and effort put into this person is well spent. i am willing to go out of my way for this person.

rayer:
P: Premium: A P code is a life friend someone that i absolutely adore and i would take a bullet for or jump in front of a speeding bus in their place...as the class gets higher the amount of ppl in those classes gets smaller.
S: Special: an S code is a spouse......and since in my culture we do arranged marriages, i would hope to become friends with him but obviously i wont know him until the wedding. i am willing to do a lot for this person but would only expect to be provided for by him in return, as far as emotions i dont expect much.
O: Order (special Order) like S/S ......this classification is reserved for my future kids.......the only ppl in the world, (if i have any) that i would do absolutely anything for them even if it means my own life....no favor or sacrifice is too big for them.
The biggest problem with friendships is getting in a situation of mutual classifications ......there are ppl that i would put in the "P" class but they wouldnt do the same for me and on the flip side there are some that would keep me in high classification but unfortunately i can not reciprocate for a number of reasons.
its a sad world and nothing hurts worse than our own emotions. but you just have to take what friendship you can get and give only what you can spare......it will never be perfect but will work for some time and most friendships will die off and few will grow, but thats the real world.