Brace yourself - there will come a moment in your life when you are the oldest in the room.
After that first moment happens, the rest only get more frequent.
Or maybe it's the first reference to a band you've never heard of, or the first time you complain about a Hollywood sequel.
We all know the effect.
It's harrowing, and was recently the subject of a reddit thread, as people revealed the things that made them first feel old.
Let us know if any ring true:
1. You’re the only one in the room who knows Mr Blobby
My co-worker doesn't know what Mr. Blobby is.
-Black_Apalachi
Picture: YouTube/screengrab
2. You haven’t seen/read Harry Potter
A guy at work was talking about Harry Potter and I told him I hadn't seen it. He asked what had gone wrong with my life that I'd never seen Harry Potter. My answer ‘I was an adult when it came out and I don't have kids’
It blew his mind and made me feel very old.
-Song_of_mypeople
3. Blind Date
I had to do a presentation to a bunch of Year 11s a few months ago. In it I made an off-the-cuff joke about Blind Date, it was at that point I found out that no-one in the audience had ever heard Blind f--king Date.
Jesus.
-DAJ1
4. Sound Blaster
Making manual changes to autoexec.bat in order to get 16bit sound in Commander Keen.
-whelks_chance
5. Being called ‘lady’ or ‘gentleman’
That and when someone says 'Mind the nice lady!' to their kid when they're about to run into me in the shops.
-tumblrthrowaways
6. Getting ‘bae’ wrong
I still read bae as in BAE Systems. I'm not good at young.
-GrantSolar
7. Being confused by Radio 1
I feel like I'm about to have a stroke after listening to radio 1 for more than 30 seconds. I have no idea what the presenters are saying, but they sound really thick. I don't get what's good or entertaining about the music, and it sounds 'cheap', like it makes me want to shout to anyone listening to it ‘but don't you understand, this was written by a computer after marketing people told the computer how to make the simplest and cheapest to produce crap people will buy!’
-WillyVWade
8. Grey…hair
Grey pubes.
-OleaC
Picture:YouTube/screengrab
9. CDs
This was a while ago but I once jokingly said to an ex-work colleague; ‘I bet you don't remember CD's, do you?!’ Only for him to reply, ‘No, no, I think my Dad used to have a few of those...’
-abacus_hatt
10. Not caring so much
When I started considering just leaving things on the floor when I drop them.
-100percentproof
11. When you realise Super Mario Bros. came out over 30 years ago
Just last week my son (ten) discovered Super Mario Bros. so I was telling him what a boss I was when I played it ‘a few years ago’, then he asked me ‘how many years ago?’ and I had to face the grim reality that it was in fact thirty.
-hapag_lloyd
12. Remembering Steve Jobs’ first iPhone demonstration
I watched the Steve Jobs keynote speech on YouTube where he introduced the first iPhone. The gasps when he showed scrolling with his finger were weird to see. You forget how revolutionary it was, yet it was only nine years ago.
-fweng
13. Seeing the computer you used in school in a museum
Seeing the same computers as we had in secondary school (small all-in-one macs with floppy drive under the monitor) in a museum.
-us_patter
14. When you refuse another pint
I was down the pub last night and my mate asked if I wanted another pint and I said no cos I didn't want to be too hung over tomorrow. F--- me I'm getting old.
-dagglington
15. Realising you’re in the ‘Overs’ section on X Factor
This year I realised I'm now in the overs category on X Factor. I'm not even old but it made me feel ancient.
-dannylafiesta
HT Reddit
More: The 9 worst parenting trends
More: The 10 worst mistakes that parents make