This reminds me of a joke my dad keeps making.
The gist of it is that neurodivergent people are like cats, and neurotypical people are like dogs, and thus, they show affection in different ways and communicate differently from one another, which the other doesn't always understand. (Most of my family are on the neurodivergent side of things)
Cats bring gifts from their hunts to show that they care about the person but have an aversion to being touched unless it's on their own terms and they prefer to just exist in the same space as others.
Dogs like to do things together, are vocal and love cuddling, they attempt to physically and vocally defend you in order to show you that they care about you.
Cat tails swinging is typically seen as a sign of annoyance while their tails pointing directly up or being relaxed is a sign of being happy and content.
Dog tails swinging is a sign of excitement and happiness while the tail pointing down limply means that the dog may be nervous.
Some dogs behave more catlike (huskies are a great example of this) and some cats are doglike (you've seen them, they fetch, they bark, etc).
And while typically cats and dogs can't read one another's body language, cats and dogs that grow up or are used to the company of one another learn it overtime. However this doesn't mean that they change their behaviour for the other completely, the just adapt their behaviour a little to make it easier on the other; they both learn to be gentler and respect one another's space and needs.
For example, at first, the dog is constantly in the face of the cat, who keeps swatting at it and hissing warnings, but as years go by, the owners start to find them laying around together. The dog learns to not be as high energy when it beckons the cat to play and does it with more care, it knows that the cat is small and gets defensive whenever the dog is too loud or moves around a lot. The cat learns that the dog likes being given physical attention, so it makes sure to be close to the dog, rubbing itself on the canine, grooming it, letting it know that the cat appreciates the dog.
They both learn patience and find a way to make their respective languages more understandable for each other.
Now I know that this sounds like this is just me making the post be about neurodivergent vs. neurotypical people through cat and dog metaphors, but this is just how communication with other people works in general. We learn to make compromises, and we learn to adapt to one another, it's a two way street, always has been as no two people have the same exact way of communicating.
Small talk is one of the things our species started to do in order to ensure that there was always someone to check up on you on some level, and to keep the community healthy, let others know that the person is safe (like @just7frogsinapeoplesuit stated), we also created it as a mean to learn to communicate with others on a small understandable level. It's a tiny conversation with no stakes, you can tell as much or as little as you want. It's meant to put you at ease.
It's the type of conversation where you can talk about whatever, bring attention to small things that otherwise you wouldn't necessarily think about while you're intensively looking at your interests. For example, you can talk about flowers, their colours, the things you want to try out at a café, tell someone about a place you ate once that you either liked or got bad service at, food recipes, wanting to redecorate a room but having trouble with picking a nice wallpaper or struggling with where to put the things you no longer need.
Small talk, when done right, is a bonding activity that tells others that you care about them so much that you're willing to let them also experience the mundane with you. It's like watching at a beautiful sunset with someone you like, in silence, and being able to appreciate the way the setting sun meets the horizon, dyeing the sky in yellows, oranges, pinks and purples as it mixes with the blue, in peace. It's a way to appreciate life, even at its most "boring" times. It's helps reset your brain and give you a new perspective. And those moments are also the ones people will end up remembering fondly, because that's when you were there, with them, appreciating life together.
