Some people are given these beliefs very young....
Place a core belief in a middle of an open area. For this belief you have to defend from another persons' counter beliefs. No bigger or smaller than yours. Most children or adolescents or adults alike. Will never have an attacker.
They begin to build structures around the belief to keep it safe while they are away. What they use for construction are bricks made out of an emotion, or thought, or combination of the two. More bricks used, the more important the core belief becomes, the more fear there is for it to be destroyed - although no belief can ever truly be diminished.
The core belief creates an euphoric state of mind. Eventually while some beliefs have houses and fences constructed around them.. A core belief, without being offended, could have a castle or fortress around them.
Some day. A protagonist comes along to try to attack the fortified belief. Their attempt is futile they can only bring so many supplies until the fort eventually outlast the ammunition.
Sometimes these battle allow the defense of the fort/castle to be improved, awareness of counter beliefs prevents their effectiveness.
Like all constructed beliefs, the fort can be broken. But, with a larger defense comes a larger battle. Even if an arsenal of offenders approach. Materials from the other structured beliefs will be taken apart and reused for the more essential core belief or beliefs.
If, or when... A core beliefs structure is near pressuring point - about to break. A lot of things can happen....
Events involving fear, anxiety, confusion - dysphoria - as, all the euphoria from believing will ever bring to you, is gone... Hard pill to swallow. Hard battle to lose.The core belief is crippled...
Ego decides what to do next.
Rebuild, re-replicate, or stop building large castles to ever experience the hard ship of dysphoria.
What are your core beliefs? Are they worth fortifying? Why?