People are hard to understand – that's well established. But why is this so? After all we are social animals, surely being able to understand each other is rather important. I believe a lot of confusion arises from centuries of flawed "folk psychology" – the way everyday people analyses each other. I believe the common understanding of personality is flawed. We tend to imagine people as a single entity: one body, one mind, with a set of properties, traits, and behaviors that add up to a person's personality.
People are like irregularly cut gems. Imagine that instead of the formal symmetry of a cut and polished ruby or diamond we have one where the geometry is chaotic, plane faces oriented and interlocking in complex non-symmetrical ways. Under any one angle some sort of structure may emerge – the faces seeming to follow a pattern, or at least there is one established order. In fact, just like any collection of shapes, stare at it long enough and it will seem as if there is some kind of ordered arrangement – the mind does not easily accept total chaos.
But rotate it but a few degrees and its appearance changes completely. The same facettes, combined with new ones, form new structure very different from the first, maybe even seeming incompatible. This is how people are. Rather than having personalities as a of single integrated entity, people posses countless traits, behaviors, beliefs, reactions, and so on. Another person will only every see a limited subset of these which normally settle into the appearence of what is called personality.
However this personality is only subjective. If we, figuratively speaking, turn the person around a new personality emerges – one we do not know and may even be shocked by. And yet this may be the "personailty" familar to someone else. And, like the gem, these apparently disparate people are part of the same structure – geometrically coherant and part of the same rock. Also, despite these apparently contradictory "personalities" the person is not mad or even "acting out of character" – it is our conception of character itself that is flawed due to our necessarily limited perception of others.
The total nature and multidudinous aspect of a human being may not be known to anyone – even the person themselves as many of these facettes may only be known through specific situations which may not arise in that person's lifetime. In a sense everyone is suffering from multiple personality disorder – but rather than attempt to reduce ourselves to a single simplified entity, we should accept and embrace this inner diversity, allowing ourselves to flow smoothly between our multifacetted selves rather than experiance these changes as an awkward clash.