Bushie quit because he grew bored with working. That's all there is to it. Everything else is a bs rationalization.
it is possible that the nerve damage became an obsessive fear rather than a post-haste rationalization. this is
not to say he would've continued working without running into this ex-mail carrier, but that his 'condition' would've seized onto something else.
ODF imagines all sorts of ailments for himself when he sitting around watching college football. when exposed to a few consecutive days' work at a grocery store, he was likely to experience significant (but not
dangerous) foot and back pain, etc. this 'connected' with the nerve story and facilitated ODF's natural gravity towards inaction, inertia.