For example, most people find their romantic partners through their circle of friends. If you are social, if you have a large circle and hang out with them a lot, it would probably happen to you more or less naturally. If you are like 25 and it did not happen, it suggests something is different - maybe you are not very social, maybe you don't have much of a circle or you have the kind of circle that is not very conductive to this and so on.

FWIW I met my first girlfriend through my circle of friends, at the age of 26. :-)