The World is a wonderful place for them, filled with interesting things, opportunities and the certain knowledge that whatever happens, they are safe, comfortable and will be absolutely fine because people will like them, they will be welcome everywhere they would ever be interested in accessing and there is absolutely no risk, physically, emotionally or financially in taking a chance.
Their comfort zone is so expansive that it's a tiny twitch to shift out of it briefly, knowing that it's easy to just pop back inside without harm.
This is both a blessing and sometimes a curse, because that then translates into taking stupid risks because they've never had to risk assess everything in advance - cars, sports, drinking too much and getting hurt by deciding to tombstone off a Devon cliff, for example - and when something goes wrong that they aren't protected from the consequences of, whether it's something physical, something financial where there is no help from anybody else because of death/job loss/disability/whatever or something emotional where they can't cope with university workloads, relationship breakdowns or suchlike, they've never been equipped to deal with it.
I think it's great for those who have had such an idyllic, safe childhood, but I do feel sorry for those who find out later that the world isn't always such a nice place - and the lack of understanding the different experiences people can have can lead to a lot of harm visited upon those less fortunate (and a shedload of offence).