When I was employed in Student Affairs/Residential Programs (running a college dormitory of over 1000 students), we would do roommate conflict mediations. There was always a tiny percentage of students involved in these conflicts who showed no sense of perspective or proportion (re: problems), no willingness to compromise, a complete inability to relate to examples I would provide, and a stubborn intractability when it came to empathsizing with other people’s viewpoints.
In almost every case, these students were home schooled.
Now that is not to say that all homeschoolers end up like this (certainly, I’m sure there were some homeschoolers in the dorm that got along fine with people). But there was something almost perverse in the level of entitlement these kids I encountered had–everything had to be catered to their will and specification, and things that would be considered “normal” behavior amongst college students (playing music, hanging out with friends on Friday nights, etc.) often was seen as completely unacceptable to them. Basic social norms of communication were foreign to them; they would interrupt, actively not listen while others were talking, and complain incessantly without even trying to solve the problem on their own. They also had an exceedingly hard time when they didn’t get their way, or were told things they didn’t like to hear (like “You’re being selfish”, “Sharing a room means having to compromise”, or “I’m sorry, but that’s simply not going to happen”).
In every case, they moved out of the dorm before the term was over. Since you couldn’t break a dorm contract without footing the bill anyway, they (or their parents) preferred to pay for the dorm and an apartment rather than to resolve their issues with their roomies.
I also have homeschooled children of various ages in my family (nieces and nephews) and though not as extreme as the cases I saw in the dorm, they also have obvious socialization issues. Needless to say, I’m sure this isn’t true for all homeschoolers, but I’ve always suspected that home schooling makes socialization in those formative years much more difficult.
Home schoolers (from my experience) rarely are far away from either their parents or friends of their parents. They are less frequently forced into situations where they have to rely on their own initiative and intuition to solve problems. Home schoolers also tend not to be as exposed to diversity–not just the multi-cultural type, but also a diversity of opinions and attitudes (say, if you’re homeschooled for religious reasons), socio-economic backgrounds (it’s harder for poorer parents to homeschool), or personality types (bullies, jerks, etc.). Dealing with the dorm examples, this was often the first time they were confronted with a variety of peers demonstratively different from themselves, and the first time they spent any significant time away from their parents. The outcome was always quite ugly, since by then, patterns of behavior are more set when you’re 18 than when you’re 8.
There are plenty of kids out there, no doubt, that can overcome these difficulties and have common sense, positive self-worth, and personable demeanors that make such socialization issues, while difficult, not a crippling issue. But growing up is hard, and it often takes most of us elementary and middle school (and beyond) to figure out our own coping strategies when dealing with other people–people you like or hate, people you are attracted to or persecuted by, people whose company you choose to share or avoid. Homeschooling very often limits the breadth of daily exposure necessary to develop those skills sufficiently.
The only thing I ever found comparable when observing in an academic setting was when I’d encounter a student who had skipped two grades (or more). Being younger than their “peers” often meant not being of age to do things (drive, drink) when their classmates could, and skipping grades usually meant you were more inclined to study, immerse yourself in academic rigor, and not get out as much with others either. Being “smart” is often a stigma enough, but being younger (and usually more emotionally immature or inexperienced) than your peers often only reinforces the difficulties of socialization.
Obviously, not all grade skippers (especially if it was only 1 grade) have these problems, but those were the two most glaring commonalities I witnessed during my time in the university system (though clearly, other, more personal commonalities re: upbringing, sibling relations, etc. weren’t things I would necessarily be aware of). Although, again clearly, there were others with socialization problems I encountered that didn’t fall into these two categories; but amongst the “worst” (the ones who had the most difficulty socializing), they usually did.
I don’t want this to be a home school hijack, but the OP did ask for examples and these were the most observable from my experience.