Genetic memory, is called 
As a hockey fan I must say it drives me crazy to see players staying down after minor, incidental contact.
And as a football fan I have to say that a minor looking contact can cause a lot of temporary pain on almost unprotected players, other than on people playing in what practically is full body armor.
Exactly, there is a good amount of simulation going on, but getting kicked in the leg with the strength a professional football player can impart to a kick… it hurts like hell.
On top of that, the one minute suspension for a player who has been medically treated on the pitch has reduced the amount of simulation significantly. That’s one of the good new rules.
I won’t argue with people who know soccer better than me. However, I have seen hockey players lose multiple teeth and spend less time on the ground.
It seems like it should be pretty obvious that there are a lot of things that can happen to you on a soccer field (a kick to the shin, for instance) which are legitimately horribly painful for 30 seconds or so, and then you’re fine. Flopping is a thing, but it’s not the explanation for most of the times players fall down and need a bit of time to recover.
Another reason for staying in the ground is that football is IIRC the sport where the players run more (as in distances) than any other, a few seconds of rest are invaluable.
I don’t deny that hockey players are a tough bunch, and I like the sport. But getting a foot in your unprotected heel or a knee to your upper leg (we call that “Pferdekuss” in German, a horse’s kick) hurts like hell. I know it from experience, I used to be a keeper in my youth.
I was once hit by a ball kicked at high speed on the groin… I was on the ground for more than 30 seconds let me tell you…
As I said, here’s a former keeper. Balls from three meters to the groin or right in the face, I’ve had it all. And it was in a time when I didn’t even know the word jockstrap or that something like this even existed. And no mask.
Are there any rules or protections for a player who might be concussed? The Egyptian player who went off looked like his head got smacked.
To a completely ignorant person like me, the grabbing of the shin and the facial expression looks so similar every time that it seems performative. To be clear, I have never played soccer not have I watched a lot of it so I am probably wrong.
Yeah, for a few years, there has been a protocol for the medicinal personell to check the condition of a player who smacked his head somehow for a possible concussion.
I can guess!
I had some trouble describing what happened to me in English, now that I’ve thought for a moment, it was like this:
I was tired and supporting my weight on my knees, my err… little football balls were hanging as much as my underwear allowed when a ball hit with great strength came from behind me and impacted just in the perfect place, for a few seconds I couldn’t even breathe.
And we have a tie game between Egypt and Australia. It’s been a decent match to watch thus far.
An own-goal by Egypt tied the game.
In my case, the ball came from the front, hit me in the balls, I fell on my back like a sack of flour, saw stars and couldn’t breathe for 30 seconds. It totally blew me out. But after 5 minutes, the game went on.
What would you do if someone kicked you full force into the shin? You would go down to the ground, rub your shin and show agony in your face, like every footballer does. Nobody can help that.
Let’s put it another way: I’m the first to admit that flopping and simulating in football are problems that don’t exist in other sports like hockey. But that doesn’t mean that football is a sport for sissies, and that you’ll never hurt on a football pitch. Everybody who thinks so has never played the sport.
I once took a point blank shot to the middle of my thigh on a cold, damp November evening and couldn’t straighten my leg for a solid minute.
And, of course, to the inevitable groin shot a time or two.