A concept may be used in two ways. First, it may be pulled out to give meaning to experiences in the past (including the very near past just seconds ago). It helps make the experience comprehensible and relatable to others. "That was a bear attack." "That was sex." "That was fun." "That was World War II." "Stupid fairies!" Second, it may be used to give meaning to experiences in the future. As such, it both orders action and provides a framework for experiences in the future. "Let's have breakfast." "I am married." "I have a job." "Are we at war?" Frequently, concepts do both - the concepts of "love" and "global warming" both interpret experiences in the past and plan and order experiences in the future. Without expressing experiences in concepts, it is impossible to bring one's linguistically-based faculties to bear on it. To understand something is to link it up with a concept or story; to communicate it is to link it up to a concept or story that is shared (and includes the process of building these shared concepts).
Bill Ellis' "When is a Legend? An Essay on Legend Morphology" (in The Questing Beast) outlines a possible life cycle of the legend. At its first stage, a legend is an experience - though it need not be a personal experience of the creator or narrator himself. Second, it is initially translated into language, quite unpolished, with many verbal stalls and formulas. Third, it is polished into a finished narrative and shared as such. Then, when everyone in the relevant community has heard the finished narrative, it exists as metonym - a reference to the story, though the story itself is no longer performed. Finally, the legend becomes a "legend report" - no longer performed as a story, hence often collapsing into incoherence when narrative devices are removed, and lacking detail and truth-negotiation. Concepts exist in the same way when viewed across time, though the word suggests something frozen at the metonym stage.
It's In The Way That You Use It
Concepts are socially created and maintained, but they are real enough to affect the world by ordering human thought and behavior. The concepts that best reflect reality - again, reality including the mutually-aware minds of human beings - will be those concepts that have been ground against the rough stone of this reality. (The excellent example given is that the person who knows most about concepts like femaleness and womanliness is the genetic male who is passing as female. This was also Dave Chappelle's joke in the selection of "contestants" in the game show skit "I Know Black People.") When a concept has frequent contact with reality, with fast feedback and a lot at stake, it will be honed to the shape of reality. The universal phenomenon of the formation of jargons reflects that frequently, when ordinary, widespread concepts rub up against a particular reality, they do not express its important parts and processes adequately. Becoming better at expressing reality, within a specialization, means becoming more opaque to outsiders. Synthetic concepts - concepts that are built out of other concepts, including other synthetic concepts - are particularly difficult to translate into the ordinary language of non-specialists.
Religions and aesthetics are composed of concepts and stories. These frequently touch on subjects not ripe for meaningful reality feedback. As they are not regularly pruned by reality, they instead optimize for other things, such as social transmissibility, organizing behavior, and providing experiences. It may be good (in terms of our own interests as experiencing beings) for them to optimize for providing experiences; it can be seen as unfortunate that frequent honing by reality probably shears off the most fun, interesting, satisfying outcroppings. It should be noted that this type of honing operates at a completely different level from the honing that natural selection accomplishes on the physical organisms that maintain the religion, aesthetic, or concept, though similar losses must have occurred on that level as well. The most fun way to perceive the world is not likely to be the most accurate.
This process of culture reaching into our minds and organizing our experience and thinking is creepy, horrifying even. But luckily our experience of this has the positive quality of averageness, everydayness, to make it work smoothly.