Subscribed on Other's Facebook Updates Without Me Knowing

I recently found out that I am subscribed to others updates.

But to tell you the truth, I don't even know that I click subscribe on their facebook profile.. I don't really know what happens there.

But thinking overnight, maybe it happens when you are trying to add someone on facebook, instead of clicking Add Friend, you click Subscribe without you realizing. It happens on me already, that's why I'm considering. And also, I'm referring to Add Friend on facebook on their profile on when Timeline is not yet used by that facebook user.

Because Subscribe button is just right next to Add Friend.  So maybe it always happens.

And you will see on your dashboard Home on facebook this if you are subscribed on that person.

If you see a triangle on upper right corner of your friend's profile picture, it indicates that you are subscribe on their  updates.

 And one thing more, I am confused on facebook subscribe matters, because when I saw my facebook Subscriptions, I just subscribe to 3 people, but when I go to my home dashboard on facebook, I saw many subscriptions, like the above picture.

What's wrong facebook?

I just want to clear it all here. Because I don't want other people think I subscribe to their updates.