For instance, I was very late to develop an interest in popular music, TV and films, because I was too busy navigating through a confusing and painful maze of bullying, sensory dysfunction and nonexistent body awareness to have much energy left for Beverley Hills 90210. This meant even if I did somehow find myself in a conversation with another kid in my year seven class we'd have nothing to talk about, because from memory they talked about nothing but 90210. Music probably came into it too, but I've just googled what did well in Australia's charts that year and the only ones I'd even heard of were The Proclaimers' 500 Miles and Four Non Blondes' What's Up, and I don't remember either of those taking St Mary's North Rockhampton by storm. Not that I'd probably noticed if they had, I suppose.
This follows you through life. There are a lot of things I haven't done which most of my cohort have. These things, or rather this lack of expected experience, continues to mark you as an outsider years after you've got your proprioception under some sort of control and learned to fake eye contact.
So, by way of illustration...
10 things I've never done (that most people my age have)
Travelled overseas. When I had the inclination, I didn't have the money. Now I have the money, but I know my limits (in terms of organisation, fatigue, and ability to navigate the unknown) better than to set off alone.
Asked someone out on a date.
Had a housewarming.
Got a phone call at an odd hour from a drunk, stoned or otherwise high friend, or been asked to assist said friend in any way. I did once help a blind drunk acquaintance take her high heels off and tuck her into bed, but that's a long story and one best not told to protect the innocent.
Supported a friend through a breakup. Not that I wouldn't if the need arose, but I've never known anyone well enough to be in that position.
Asked for someone's phone number for a non-work reason. I do a lot of asking for numbers for work, because ironically I communicate for a living, but outside work I'd rather try to convert those lions to veganism than hit up a stranger for their phone number.
Seen Back to the Future or Star Wars. Of course there are an infinite number of other films and TV shows I haven't seen, music I haven't heard, and books I haven't read, but unless you've tried to navigate the 21st century as a person who doesn't particularly know about those two film series, you wouldn't believe just how often they pop up. There's a PhD thesis in there somewhere, about their role as modern myths and cultural shorthand.
Done an assignment the night before it's due, or not done it at all.
Been in a wedding party. Until last year, that could have read 'been to a wedding'.
Been to a music festival. Work once shoved me in the direction of the Gympie country music muster, but that doesn't count because I was working backstage rather than being an actual festival attendee. I didn't actually do any of the things one does at a music festival. Whatever those are.