Like the fact that a female singleton pretty much has to come up with a date to weddings if she does’t want to dance alone. Your 30’s is too old for the cute, single guys to take notice (the 20-something girls get all that attention) and brothers (unless they are related to Julianne Hough or Lacey Schwimmer) are pretty useless.
Or that singletons are generally doomed to eating the same dinner at least twice in one week. This is because it’s hard to cook for one person and even harder to get up the motivation to cook for one person every night.
And that the median age of a singleton’s circle of friends often keeps getting younger and younger. Not that one doesn’t have friends near age 30 or older but these folks are usually married and therefore have less time to hang out or are more difficult to schedule with.
Aforementioned younger friends declare that they will join a convent if they aren’t married by the time they reach your age. (And then realize who they have just said that to and turn bright red.)
Newly-wed younger siblings and friends temporarily believe you are less capable than they are of finding love. Even more amusing that immediately after the wedding they feel qualified to give dating advice.
People in general believe you to be younger than you are because you aren’t married with a family. (Win!)
Some friends will announce to everyone that they are trying to find you a husband/wife. Meanwhile other friends will assure you that you’re too good for anyone the first friend could find.
Being an aunt/uncle in your 30’s is the best of both worlds. You get to enjoy playing with nieces and nephews, taking them to the movies, and get mistaken for their parent. Yet, at the end of the day you send them home and then sleep like a baby.
Your newly single friends suddenly want to hang out with you. This is mainly because they want to learn your ways like a sociology study: “How to stay single without becoming a crazy cat lady/man.”