From Writers Helping Writers:
Debilitating fears are a problem for everyone, an unfortunate part of the human experience. Whether they’re a result of learned behavior as a child, are related to a mental health condition, or stem from a past wounding event, these fears influence a character’s behaviors, habits, beliefs, and personality traits. The compulsion to avoid what they fear will drive characters away from certain people, events, and situations and hold them back in life.
In your story, this primary fear (or group of fears) will constantly challenge the goal the character is pursuing, tempting them to retreat, settle, and give up on what they want most. Because this fear must be addressed for them to achieve success, balance, and fulfillment, it plays a pivotal part in both character arc and the overall story.
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Fear of Isolation
As social beings, it’s common for human beings to seek out others for support, companionship, or safety. But alone time is also important for people to be able to rest, reflect, and recharge. And no matter how social a character is, there will be times when they’re on their own and need to be comfortable with themselves as company. A character with a fear of isolation will struggle in these moments due to the intense discomfort that arises when they’re alone.
What It Looks Like
Having a large family
Pursuing a public career or one that requires the character to interface with others
Living in a highly populated area
Having an overly active social life
Always having a significant other
Being in multiple romantic relationships simultaneously
Flourishing in large groups of people
Being the one who coordinates get-togethers
Keeping the TV on all night as background noise
Working in an office rather than remotely
Calling people often to chat
Being the last one to leave the party
Making do with surface-level relationships when deeper ones aren’t available
Common Internal Struggles
Needing downtime to decompress but not wanting to be alone
Being stressed by a packed social calendar yet continuing to fill it
The character fearing their inner thoughts and emotions when they’re alone
The character fearing they cannot take care of themselves on their own
Negative thoughts and feelings taking over in the absence of other people
Feeling anxious, unsafe, or panicky when alone
Being assaulted by inner demons and bad memories when no one is around
Link to the rest at Writers Helping Writers