When I do something, turns out other people do it around the same time

Seriously though this happens to me sometimes as well.

I really think it is just a coincidence. I don't see how it could be anything else.

It's called a coincidence and you're young, so you don't recognize that human beings like to try and make patterns out of things even when there are no patterns there. Lots of people have low appetites, lots of people play a game that has several million users, lots of people notice when their close friend has a crush on another person they know. There's nothing mystical or magical about it, it's just coincidence and observation of it. You're trying to make sense of something that isn't there.

The reason it feels as if everyone is experiencing the same things you are, is because they are. The only difference is you are now more cognizant of those similarities. Take your relationship for example, you're noticing more people in relationships than before because you are more prone to notice it, due to your relationship. Does that mean there are more relationships now? No, just that it went unnoticed before.

quote cheatdude

Yes, you're right.
It's just a thought I had. I thought the case had a name, but guess not.
Still, it seems to go to a point where there's always at least one similarity between two people, so there's no one who feels differently from everyone (and by everyone I mean millions or billions of people).

I think the closest thing to what you're thinking of is Synchronicity.

Though it doesn't totally cover what you're experiencing, it's one of the more prevalent philosophies that begins to cover it.

In a boring reality, what you're really experiencing is simple coincidence. Things that would ordinarily go unnoticed by you, (such as similar phones being used by others), are suddenly at the forefront of your mind.

You come into possession of a new phone, and suddenly you start to notice other people with the same phone. This isn't caused by some sort of unexplained phenomenon, but rather the fact that you're more perceptive to things that have some familiarity to you. It's just how our brains work, and sometimes it happens so far in the background of our conscience, we don't readily understand why it's occurring at all.

Once you have it, you look for it.

I was watching this interesting theory in a show called Through the Wormhole. Basically has to do with the earth's magnetic field and the human brain being affected by it. Basically everyone on earth is connected through it, so it's not a rare thing for groups of people to have similar experiences or urges. They did a controlled experiment on it and it was all pretty cool, if you ever get a chance to look the show up.

Friend, you're possily what can be referred to as a leader.
In reality, you're probably just an inquisitive person that hasn't leant applications of probability in maths. There is a slight chance in every situation that an aspect is partaken by another. So if you look at the relationship between the chance occuring and all situations you've experienced, you'll see the probability equivalates in it happening every so often... Let's call it probability.