An expression that was used in How I Met Your Mother.
It's a warning that is trying to avoid dating with people you have to work with, be in the classroom or people employed in your favorite pub, gym, club... Or a friendship with your new neighbours.
Platinum rule has 8 steps.
Step 1: Attraction - it's so easy to surrender.
Step 2: Bargaining - the time when you try to persuade your friends that platinum rule doesn't apply on you.
Step 3: Submission - everyhing seems alright.
Step 4: Perks - like: we can be together all the time - but that's crazy...
Step 5: The Tipping Point - now you realize that maybe it was a big mistake.
Step 6: Purgatory - now you know for sure that it was a big mistake.
Step 7: Confrontation - time to end the relationship or friendship. Normally starting with words: Well, I really like you but ...
Step 8: Fallout - because it's a person that you have to work with you must face the consequences connected to what happend between you.
Maybe there is also Step 9: Rescue - everything should be ok since this point.
X: Oh, i met a great girl today at work. And she's really hot. I would like to go on a date wit...
Y: Forget it, don't you know the platinum rule?
X: What rule?
Y: I'll explain it to you. Step 1......