受骗的人生Q：What is the stupidest lie ever told? 被坑的最惨的骗局？
A3: No one can beat this.
关于爱情的提问：How do you know if you've found "the one"? 如何知道自己找到了那个“TA”?
Answered by Sasha Katsnelson:
Short Answer: When someone's good enough, you do what Jack Stahl suggests and just start behaving as if that person is "the one"
Long Answer: I would define "the one" as person with whom your joint utility functions are maximized when you are together. A sort of global maximum of the set of all of your potential romantic relationships. In my experience, allowing the idea of finding "the one" to govern your decision making requires either a strong belief in fate/predestination/magic or a great amount of comfort with self-deception.
Realistically, you will probably never get a chance to try out romantic relationships with all other humans, so what you're actually shooting for when you look for "the one" is the local maximum. The person who you are currently able to date who will bring you the most joy.
The issue with the idea of "the one" is that, regardless of whether you are actively dating or in a long-term relationship, over time your pool of potential relationships grows, so what had been a local maximum may cease to be one. You may justify the fact that you are unsatisfied in your relationship through the rationalization that the person you are with is not "the one" you are fated to be with, but what you actually mean is that the person you settled for when they were your best choice has ceased to be your best choice.
To further complicate the matter: you, your partner, and both of your utility functions change over-time. The girl who was your perfect high school girlfriend may change completely in college, or you may reinvent yourself, or you might discover a new definition of perfect girlfriend. So even if you should happen to find your global maximum, "the one," you may discover in a few years that your definitions have changed and she no longer fits the bill.
When you have nothing tying you to your partner - no contracts, no kids, etc... - and plenty of time to explore, it may make sense to keep searching, to keep optimizing your personal life. But over time the costs of switching partners increases, the likelihood that you (during your lifetime) find a new partner that is better than your current local maximum decreases, and your utility function becomes more stable. At some point, depending on your relationship, your interests, your goals, and your partner - there is value in willingly reducing your options and committing to someone. You agree to behave as if that person is your "the one"