Joking aside, for Bob to give off the kind of warmth and comfort that he did, I’m sure he had to work toward it, and I imagine he had personal reasons.
A quick DuckDuckGo later…
Interesting. His chill vibe doesn’t sound to be rooted in anything as traumatic as I worried, but it does seem to be intentionally cultivated:
“Having held military positions that required him to act tough and mean, “the guy who makes you scrub the latrine, the guy who makes you make your bed, the guy who screams at you for being late to work”, Ross decided he would not raise his voice when he left the military.” - Bob Ross - Wikipedia