Being doomed to a mediocre and insignificant existence

Public speaking / public humiliation

Discovering that they may actually be an idiot

Sustaining severe brain damage or developing a neurological disorder like dementia or Parkinson’s disease

Dying before they’ve achieved anything

Being taken advantage of because they didn’t know something

No internet

Losing someone precious to them

Losing their memory

Failure and Rejection

Getting locked into a commitment they can’t back out of

Finding out that they’re actually more of a sappy feeler than a thinker

Having perfect and complete knowledge of everything in the universe and having nothing worthwhile left to understand or figure out

Being unable to create anything new because every possible thing that could be created already exists

Dying and finding out God exists and realizing that the lame sensors were right