First of all OP dont take the opinions of those whom have worked for UPS their entire lives too seriously. Quite frankly they dont know any better as they have never worked in the real world.
Second this job is great if your at the top of the pyramid ie full time driver max progression. Everyone else is on their own fighting for the scraps.
Third nobody i know has retired from this job without sustaining some type of mechanical injury, shoulder or knee problems, bad back etc. It is just part of the job for most.
Finally ans most importantly consider the fate of our company and again ignore the lifetime upsers they really dont know any better. We have been losing market share to fedex/usps for years. Even worse companies like amazon, uber and a host of app based company's like favor or uship will continue to steal the "good stuff" ie small parcels and envelopes. I also question whether we will even still have health insurance after the obamacare cadillac tax kicks in. Sometime after 2018