Warning: Unsocialized homeschooler ahead!
Heather covers socialization well here
but a quote
I understand that children play together in ways adults can't comprehend, and that children, when playing together, reach levels of imagination unfathomable to adults. But aren't they already getting more time at imaginative play than their public school counterparts with their siblings at home? A neighbor kid or two? Can they not learn they can't always have their way from their parents? From the fact that they're all out of blueberry pancakes at the diner today? From the car repair that prevents them from going to the amusement park? LIFE doesn't let you have your own way all the time. Can they not learn about rules and how to follow them from their parents? From the "No Running" sign at the swimming pool? From watching Mom get a speeding ticket? LIFE shows you there are rules that must be followed. Interacting with other children, in school or in homeschool group playdates, does not teach kids about the real world. Interaction with the real world does.
Emotional bonds with other humans is necessary for proper mental stability. That those humans be unrelated to you is not. We homeschoolers need to stop agreeing with the experts in the necessity of socialization with justifications, explanations, and excuses. Socialization? Who the hell needs it?