Inner and Outer Narratives

[image error] In our interactions with people, we often assume that what we see is the full extent of their personality and inner life. Unless we have an extended relationship with that person, and peel away the exterior layers, we don't often get to see if there is a dissonance between what they experience and what they present to the world.
When constructing a fictional character, you have an opportunity to explore this dichotomy as much as you like. Your character may wear their heart on their sleeve, or they maintain one public persona while living a very different interior life. The effort required to prop up their image may be a subplot in and of itself, causing them conflict for myriad reasons-- the stress of pretending to be something one isn't, the demands of a job that requires a particular persona, or any other conflict between presentation and reality.
Furthermore, perception of the character by others may not match up with their inner life due to simple misinterpretation. For example, a friend told me she was amazed by how 'spontaneous' she found me. As a person who is less than keen on major surprises, I like to plan things in advance, but I do so quietly-- to an outside observer, my actions seemed spontaneous, because I hadn't spoken about my plans in any serious way. Similarly, a character might present as disinterested when instead they are observing closely rather than engaging; someone might be seen as unflappable when in fact they are numbed by trauma; countless examples are possible. The character's persona may not even be of their own conscious making.
A public persona can be situational, instead of a permanent barrier between the character's true self and the world. A shy person may enjoy acting and take over a stage, but revert to their more quiet self when with friends, or someone who cultivates a tough, confrontational presentation in their job may show tenderness with their children.
As the author, you can bring the reader into the character's head and show their inner life, as well as the reactions of others around them. This certainly isn't required, and characters who present their true selves most of the time can be just as interesting as those who hide behind a mask. Either way, it's always good to use your insights into the character's thoughts and feelings to give the reader further insights and deeper conflicts.