You meet new people every single day, even though you aren’t formally introduced. You stand with them in elevators, walk by them on sidewalks; they serve you at restaurants and get in your way at the fountain drinks; they sit with you in traffic and cut you off while talking on their cellphones. Every day you pass potential friends or lovers, maybe someone you could help or someone who could help you. They see you or you see them, or sometimes both, but only for a moment and then it’s forgotten. Even though you miss these opportunities, you don’t care. You don’t even notice. You don’t mind that they remain strangers, because you didn’t know them anyway and you’ll likely never see them again.

Every so often, a person emerges from the shadows of anonymity — a friend introduces you to her friend, or the person beside you strikes up a conversation, or some other happenstance. If the conversation is mostly impersonal, you perform the expected niceties and small talk that allow you to get from point A to point B as pleasantly as possible. Sometimes the conversation manages to get personal, but even then, you usually don’t feel pressured to make much of an effort. You’re not invested in the outcome so you’re not self-conscious. And if the conversation is interrupted or ends awkwardly, you don’t mind. After a brief moment of familiarity, the person becomes a stranger once again.

But once in a while, something peculiar happens. From this huge pool of unknown strangers and temporary connections, you meet someone who, for whatever reason, you want to have a better relationship with. Maybe you’re attracted to the person and your interest is piqued; maybe it’s your future mother-in-law and you want her approval; maybe it’s a coworker you respect and you’d like reciprocation; maybe your boyfriend, girlfriend, fiance, husband or wife has been unfair recently. Whatever the case, you care what that person thinks about you and how they act toward you. You’re invested in the outcome, so you feel compelled to make an effort; you may even be self-conscious. If a friend asked you why you care about this person, you might not be able to explain why. Or you might be too embarrassed by your reasons to admit them. But even if you try to explain, your friend probably wouldn’t understand anyway, because your reasons are so personal, and because in actuality you don’t really know why. It’s such an irrational, subconscious thing.

So what if the person just isn’t giving you the time of day? What if they aren’t reciprocating your effort or your interest? What do you do when, for reasons out of your control, it seems impossible for you not to care about your relationship with someone? Well, your initial response to this disappointing realization will be as irrational and subconscious as your feelings for the person. Depending on your disposition, you start by feeling either inadequate or indignant. But when those feelings pass, you’re still left with the burning question of what to do next. What’s worked for me, in relationships both romantic and platonic, is a simple idea that was difficult to learn:

Meet in the middle.

If you make an effort and put your best foot forward — if you go to “the middle” — then you’ve done your part, and that’s all you should expect from yourself. If the other person doesn’t make an effort, well, what can you do? Whether you know why isn’t as important as knowing that you tried. Now it’s their turn, and all you can do is wait, patiently, at the middle. But this isn’t a stop-your-world kind of waiting. You’re not sitting there thinking about the person, hoping they make the right choice, investing yourself emotionally in their decision. Your life goes on.

Look, so much of what happens in life is out of your control. If you focus on those things, you’ll surely be overwhelmed by life’s infinite possibilities. Instead, focus only on what you do have control over — your actions and your attitude — and life will be a lot less stressful.

Just to be clear, here’s what I’m not saying: I’m not saying you should always wait for the other person to make the first move. (Take chances. Break the ice.) I’m not saying you should always expect something in return. (Give more than you get. You can scale back later.) I’m not saying that the solution to everything is compromise. (“The middle” is about making effort, not making solutions.) And I’m not saying you should give up on people easily. (No one’s perfect. Everyone makes mistakes.)

I am saying to be reasonable and pay attention. And I am saying to be selective about the people you invest time and energy into.

It’s tempting to go past the middle, overcompensating for another person’s lack of effort with too much effort on your part, especially when you want so much for the relationship to work. If you catch yourself doing this, STOP. RIGHT. AWAY. Chances are, the other person isn’t thinking about your relationship the way you are. Or they just don’t care as much as you. Neither is wrong in the moral sense; they’re just wrong for you. Don’t waste any more of your time and energy or else you’ll miss out on someone who is worth all that. Someone who, without having to try, cares. And because they care, tries anyway.

In a way, while waiting at the middle for the other person to get there, they become a stranger again — one of the billions of people in the world whom you don’t yet care to know. Who knows: maybe, like strangers sometimes do, they’ll surprise you. And if they don’t, well, you’ll be too busy living your life to notice.