Comedy, as every budding stand-up learns after their first set goes down like a sack of pancakes, is subjective. Not everyone finds humour in the same things, but one thing that we fickle humans do share is the infectious nature of laughter.
When someone else is laughing, we instinctively want to get in on the action, and so the act of that person laughing makes us laugh. And when we start to laugh, they start to laugh harder. And then things can get out of hand.
Here for your merriment and mirth are a hand-picked selection of the greatest videos of other people laughing that the internet could provide. And yes, they are contagious.
1. "Contagious Subway Laughter"
If you ever needed proof that laughter is contagious, this is it. You can literally see it spreading down the subway car, claiming more innocent lungs and diaphgrams as the fever takes hold. They say that laughter is the greatest medicine, but on the strength of this video, it could be used to disarm an entire country.
2. "Sending my friend into the wrong house"
Normally when you prank a mate, you have to stifle your laughter so you don't give the game away. But when your friend is on the other side of the road, walking into a complete stranger's house that he thinks is yours, you can laugh until your eyeballs bleed. Which this guy almost certainly did.
3. "I'm comin' back in"
If you love a good wheeze of a laugh, this is one to wrap your ears around. But get your eyes involved too, 'cause the sight of a man falling over has never been funnier.
4. "This goose has killed before and he'll kill again"
Geese are evil, this much we know. But are they as evil as laughing at someone being attacked by a goose? No. They're more evil. They're incalculably evil. Laughing at someone's misfortune is about the only positive outcome involving a goose, besides Christmas Dinner.
5. "Heavy Rain Chase Fail (Hilarious Laughter)"
The problem with promising hilarity is you inevitably fold your arms, lean back in your chair and go "Oh really? We'll see about that." So do that now: fold your arms, lean back in your chair, and do your damndest not to laugh along with this guy. You'll be on your back before you even realise you've fallen off your chair.
6. "Mom has gotten into the wrong car"
It's one of those 'you had to be there' moments. "Guess what? My mom got into the wrong car yesterday, it was so funny!" "Guess what? That's the most boring story I've ever heard, I'm breaking up with you!" But thanks to the quick-wittedness of this suffering son, we actually do get to be there.
7. Skype Laughter Chain
If you've not seen this already then hoooooo boy, you are in for a treat. A baby has a funny laugh. A guy with a funny laugh laughs at the baby with the funny laugh. An older guy with a funny laugh laughs at the younger guy with the funn- you get the idea, just watch it.
8. "He said lock the door"
As our humble narrator and chronicler tells us, this is indeed some bullshit.
9. "Funny prank to hotel (Indian accent)"
While there's nothing particularly amusing about doing a stereotypical Indian accent, there is something very funny about listening to someone completely let go of their professionalism in the face of increasing stupidity. Never has the prospect of getting F'd in the A produced such hysterics.
10. "We asked the groomer to give our dog Stains a 'Lion Cut'"
So there you have it: if you ever find that your dog just isn't bringing in the laughs that it used to, you know what to ask your dog groomer for.
11. "I WISH I WAS A BALLER"
Just wait for it. You won't see it coming, but you'll never forget it.
12. "The Plumber"
Do you know something? I don't think that man was a real plumber after all.
13. "Golf swan attack"
Ahh screw it, let's have another bird attack to end on. Beware the moment at 0:43 where the guy filming turns into the spawn of Satan.
Related: These Hilarious Kids Detention Slips Are An Inspiration To Us All