Belief is necessary when evidence is lacking to support a story that challenges common sense, reason, and/or historical, physical, or experiential reality, and where this story is crucial to the foundation stability (real or imagined; psychological, or political) of the believer. This is the need. Belief is fallen upon when it supports the maintenance of desired emotional states and the avoidance of undesired emotional states, and self-interest. This is the inspiration for it.
We all have certain beliefs at certain times which fluctuate to support our immediate needs. These particular beliefs (expressed orally or not) may or may not coincide with and/or support our foundation beliefs, which when conflicted with, cause no major dilemmas, unless of course they involve religion. Foundation religious beliefs, when in conflict with the visceral needs or perceived needs of a person (be they physical, psychological or political), if persisting over the long term-and if denied and ignored-result in guilt, fear, and finally, neurosis-as the believer creates fantasies s/he lives in temporarily, in order to justify or reconcile his or her diametrically opposing and irreconcilable actions and beliefs, which cause conflict with the believer’s professed behavior.