Something that everyone has done, but you haven’t lived until you’ve done it: Staying overnight alone for the first time, on your own, to your own devices, with nobody nearby responsible for you. My first night was in Kendrick’s Boarding House on St. Louis Street in Baton Rouge, after two semi-qualifying nights on a Greyhound bus.
What do you mean my particular preferences don’t have universal validity? You haven’t lived until you have visited my favorite holiday destination. Really, that’s the criterion. Sucks to be you, hundreds of billions of people since the dawn of the human race who haven’t, your lives are only pale simulacra of real existence. And if you are among the chosen few who have, and you didn’t enjoy your holiday, sucks to be you even more. Your lives are officially pointless suffering forever, nothing but misery and torment until you die.
BTW, my favorite holiday destination happens to be Gävle, Sweden. Buy your tickets today! They have mööse, and the Gävle goat! What are you waiting for? You want be alive, don’t you?
Any løveli lakes nearby? Does it have a wøndërful telephøne system? 
I just did. Now I can touch music.
“You haven’t really lived until you’ve experienced …” is smug. I can not fathom actually thinking it let alone saying it to someone.
IMO the statement is smug, judgmental and presumptuous 
“You haven’t really lived until you’ve experienced X”
Well yeah, it is pretty cool. Unless you get the cheap shit that’s cut with a ton of meth.
winner 
You haven’t lived until you’ve been deep inside a woman.
You haven’t really lived until you’ve experienced birth. Hope that’s not too political.
Which reminds me: you haven’t lived until you’ve watched Monty Python and the Holy Grail.
You haven’t really lived until you’re NOT the one the police car is after…
Here’s the thing, there are a number of experiences that I truly believe are life altering, but if you haven’t had them, you won’t understand, and no amount of talking on my part is going to make you understand. You have to experience it for yourself.
It’s like when your friend is dating someone who is no good for him/her. You see it. Everyone sees it. It’s wasted effort saying anything about it, because they’re not going to figure it out until they see it for themselves.
So… infertile people are the undead?