What is "Real"? How do you define "real"?
One of the oldest could still be among the best: It is to have effectiveness or influence -- to be causal. Or at least the appearance of it, which is arguably all there ever is. But then that would make a psycho's hallucination of dead Aunt Martha into something that is responsible for affecting his behavior -- orders from the subjective phantom turned him into a killer, rather than scattered neurons firing or wayward biochemical levels. So one level having more privileged causal status than another creeps in.
Likewise, we do not know whether there is another person in another world at the same time controlling what we see. Our wildest dream may be real.
Some of the wilder speculations tend to result from focus on what's possible from the standpoint of the individual (i.e., the standards for either "real" or "what's really going on" can be more lax). Incredibly, the individual has forbidden and immoral hopes available that cannot be seriously entertained publicly, though they be utterly absurd from the POV of the other half of the dichotomy that he/she is a card-carrying member of....
And in reference to that other half, the possibilities get more practical and restricted when considering what is tenable for a group or society. The latter (or those that are spokespersons for its "consensus") can presume by default or necessary prejudice that either the existence of community or that of a larger environment have complete independence from any particular member. (Unlike for the individual, solipsism [etc] here is not even a possibility, though providing amusing exercise, etc).
This lofty status might be considered a not always mentioned part of society's definition (or any environmental collective), and thus going against it would be to contradict an aspect of its very nature. As well, its institutional processes could be said to have "far less doubt" about its privileged position than what the individual does (due to the latter having been thoroughly conditioned by the former since birth).
There can be exceptions, though! A cult might accept that it existed only as a fantasy of Bob, if Bob was the cult's Leader. Yes, smaller groups may not always triumph over the individual, at least up to the time that they decide to hang a failed or exposed Leader.
The individual might also question if words like "society" and "community" refer to anything at all that could be considered a coherent entity. Unfortunately, similar criticisms could be reversed upon the individual. Regardless, each seems to have some degree of "effectiveness", depending on how a particular system is evaluating appearances according to its standards, methods, and biases.