Seriously. Stop it.
We've all been there.
You're standing with a group of people at a party (not good friends - acquaintances at best) and you're halfway through an undoubtedly fascinating anecdote about when the girl in the office said she thought Stonehenge was a kind of way to cook a pizza when a knowing, and completely slap-able, smirk crosses the faces of a happy couple standing side-by-side in the Annoyance (which is the correct collective noun for a group of half-strangers thrown together at a party - look it up).
An "Annoyance" of Acquaintances
Simultaneously, they say into each other's eyes (literally, they say it into each other's eyes) "I'll bet he keeps his tent clean!" before sharing a sickening, saccharine giggle and giving each other an "I'm going to die with you and there is nothing I can do about it" eye-embrace.
But it goes on. They aren't happy being enveloped in their cocoon of self-imposed reaction-limitation. Oh no. They want you all to feel the warmth and love of their shared, and mostly wasted, past as much as they themselves feel. They don't want you to feel left out. That just wouldn't do at all.
"Oh sorry..." (pretending they are in any way aware that they have interrupted you and that they in any way care), "...you see, we were in Madrid and staying on a terrible campsite. There was this guy in the tent next to ours..."
Have you finished your amazing office-Stonehenge-pizza story yet? Do they care?
"...and he came out of the front door this Sunday morning..."
Okay, we get it. You spend a lot of time together.
The in-joke should never become an out-joke.
I'm sure "At least it's not raining feta cheese", "I'll bet she can't walk past a Beetle either!" and "But he does a great Morgan Freeman impression!" all have amazingly cute and warm back-stories (apart from the Morgan Freeman one, which sounds a bit racist and you should know better), but all you are doing is reminding everyone else unlucky enough to be within earshot that your lives are drab, predictable and insular, and by extension so must our lives be.
Now, back to my Stonehenge-pizza story. It's an absolute beauty...