Just came across this in a novel I'm reading and it struck so true for Him Outdoors.
Imposter Syndrome - High achievers are convinced they're flying by the seat of their pants, about to be unmasked at any given moment and found wanting, not really worthy of their elevated positions or their impressive salaries. And the longer they stay away from the office the more likely it is that someone would realise they weren't needed at all.
However much external proof of their abilities they have - academic qualifications, job promotions, salary hikes - they put all their success down to luck or timing or contacts, anything, in fact, but their own abilities and perseverance.
from Fifty is not a Four Letter Word by Linda Kelsey
It is a very stressful way to live. After 20 years in Marketing, having reached the (literally) high levels of an office in Hong Kong, enough was enough and he downsized to working in a marina on the south coast of England. Now spends his time labouring, and loving it.