In person social life.
One of the jobs of a parent is to oversee the social life of their children. Each one has their own personality and preferences, most of which they can’t articulate until much later. So parenting is detective work. There’s no way to know which children will hit it off and which children will become bosom enemies until they interact.
I have seven children; the oldest was 15 when his youngest brother was born. They loved to laugh and make faces at each other, and then one moved away. The older children had plenty of opportunity for social interactions just with each other, besides many children in our neighborhood. But society has changed. Most households in my neighborhood have no children, and those that do, are busy night and day with school and sports. I have to work to get my children play time in person with other children. They still interact, but all online.
Talking online is good, but our children need in person social skills. They won’t learn polite behavior without it. Children can be cruel; bullying is an issue. This is why you need to actively meet up with other families. Find opportunities to play freely, with minimal supervision. Meet their friends’ parents. Plan to get together and make it happen. If your children don’t mesh or you don’t like the parents, don’t fret; look around for someone else to meet up with. Put yourself out there, as your energy allows; show your children how to introduce themselves and how to set boundaries for appropriate behavior.
The payoff is when your child finds someone they like and keep up the relationship, when you hug another parent and commiserate over challenging children, when your children see someone who needs help and automatically head over to help. This is how we find joy.