I've enjoyed coming back to SF, but I don't miss the one-upping or the know-it-all, condescension that is so pervasive on here. It's not just on here though, if we're honest. I see this behavior in the workplace, politics, even with some of my friends. Maybe the internet makes it much easier however, for people to look at others as opponents, I'm not quite sure.
It's an interesting dynamic, and not uncommon on the internet. We see this kind of thing play out on social media, too, at least where strangers are involved. Twitter is a good example (although I don't really use it, so can't comment much from direct experience).
One relevant feature is anonymity, I think. People who feel like they are not accountable for what they say or write (because nobody is likely to work out who they are in "real life") can feel less encumbered about expressing their "true self", in some ways. If they are the kind of person who enjoys putting others in their place, or somebody who thinks that life is some kind of power game, then that attitude is more likely to get free reign on internet discussion platforms.
Anonymity helps because it makes people less accountable. They can get away with behaviour that would never be condoned among their family members, work colleagues or (in some cases) friends. If they insult somebody on the internet, or troll them, or get into a flame war, that has no real affect on their reputation, outside the particular forum in which the behaviour occurs. Few meaningful consequences mean that some people feel free to let their worst side out. Moreover, if the online consequences start to stack up too much, it's a simple matter to adopt a new anonymous identity and start again.
When it comes to one-upmanship, I think we mostly see that kind of thing from insecure people. To feel better about themselves, they think they need to pound other people down. It's a zero-sum game for some people: one person's gain must be another's loss, in this mindset.
In some cases, the people who make the most ostentatious claims to intellectual achievement - like the ones here who claim they have proven Einstein wrong, for instance - are the ones who are the least secure in their own knowledge and abilities. These people are usually crying out for somebody to notice them, and they perhaps think they can achieve that by making grandiose claims about themselves.
The other elephant in the room is this: it's usually the men. That's not to say that women are incapable of one-upping or condescension. But in my experience, the most arrogant know-it-alls are almost invariably men. The reasons for that are complex, too, social and probably also evolutionary, to an extent. The desire on the part of some men to assume the position of Alpha Male is conducive to posturing and to making everything a contest - especially when one is perceived to be "competing" against other males for the "top dog" position. On an internet discussion forum like this one, "top dog" is presumed to be the smartest, most knowledgable, or wittiest member, so the males to whom these things are of prime importance try either to compete on that basis or to bluff their way through.
Is it a mindset, to want others to believe that you're the smartest person in the room? Is it healthy to act like this? I don't think it is.
If you're the smartest person in the room, you should find a new room. - Unknown author
It's definitely a mindset. Personally, I have met quite a few people of limited life experience who have this kind of attitude. Their mistake, more often than not, is to assume that because they are the smartest person in their small and socially circumscribed peer group, they must necessarily therefore retain their position as the smartest person in the room when they interact with strangers.
There's also the Dunning-Kruger effect, in which people of low(er) capability are unable to accurately access their own relative level of expertise or the relative expertise of others. The smartest people tend to be people who are acutely aware of all the things they
don't know. Meanwhile, the self-appointed "smartest people in the room" think they can match it easily with Einstein.
I've personally met a few Nobel prize winners and other award-winning individuals. In most instances I have found these people to be patient and eager to share their knowledge, as well as eager to help other people by applying their expertise. I have met people who can run rings around me when it comes to certain intellectual pursuits. With that kind of real ability, there's no need for one-upmanship or posing. The proof is in what these people produce. Meanwhile, the posers spend so much of their time
asserting their supposed superiority that they never produce anything of value.