Blind-spots built in as a backdoor by whoever built the technology now running in your brain (if you’re reading this 15-25 years in the future):

Narcotics and hallucinogens are trifles compared to ‘mascons’, which are so powerful that they mask whole swaths of reality.

Trottelreiner explains, “[mascon derives] from mask, masquerade, mascara. By introducing properly prepared mascons to the brain, one can mask any object in the outside world behind a fictitious image–superimposed–and with such dexterity, that the psychemasconated subject cannot tell which of his perceptions have been altered, and which have not. If but for a single instant you could see this world of ours the way it really is–undoctored, unadulterade, uncensored–you would drop in your tracks!”

Remember, we have lazers!™