For years it's a genuine concern. If you have a party, will anybody come? Do you get enough text messages that aren't just from your mum or Domino's Pizza? And exactly how many non-family birthday cards did you get last year?
At school, it always felt like size mattered in the chums department. The bigger the group you were a part of, the smaller the chance that you would find yourself sitting alone in French with nobody to tell that you'd been "à la piscine" at the weekend.
And at university a heavy group of pals meant people to sit sleepy-eyed with in lectures, to consume large sandwiches with at obscure times of the day, and to go out with of a Wednesday evening, rather than sitting at home doing a glossy magazine quiz about which FRIENDS character best reflects your personality. You already knew the answer to that anyway. (Gunther.)
And that's not to undermine those friendships - they're the making of some of the best days of your life - it's just impossible to keep up with that volume of people once real life starts getting in the way.
The combination of going to work, eating meals, sorting through your post, washing clothes, filling the dishwasher, entering online competitions, watching The Magaluf Weekender, and actually going to sleep for more than four hours a night dominates most of the week. It's a wonder you can keep on top of what's going on with you, let alone anybody else.
So if you do manage to spend time with another human being - aside from your colleagues, the dude at the sorting office and your grocery delivery man - it's because you really want to.
And now that you're an adult, though you don't demand much of that person in terms of time, you do when it comes to quality of friendship.
If I meet up with a pal and I ask how they are, I'm looking for a proper answer. I'm not looking for a fluffy "Yeah sure everything's fine - shall we get the chicken?" response (although my answer will of course always be Yes), I want: "Right, strap in for a full-blown analysis of my life". If I didn't care then I wouldn't have blocked out my Thursday night; I'm not exactly Mrs Popular but I definitely could have been doing something else - you do know that Eastenders is shown on Thursday evenings, right?
And of course it works both ways. I want to know the ins and outs of what's happening with you and then you, dear friend, are going to get the precise same from me. I have a husband who doesn't seem to understand the meaning of "Please unplug the iron", a fringe I can't control, and a marshmallow habit I fear is getting out of hand - who else am I going to talk to about this sh*t?
Because those are the chums that are really worth giving up a night in front of the telly for. And that, my friend, is no small compliment.