This, if I might be allowed a measure of whimsy, is the result of a collision between balder and dash at the intersection of Crazy and Stupid. Every God-damned day, Mike and John stumbled into their houses as if they'd never worked a day in their lives after doing rather light work. Since dealing with the public and shuffling papers isn't really all that taxing despite being subjected to the horror of being told what to do and to not deviate from instructions even if it was 'boring', the only reason that either of them should look like the walking dead is if they'd picked up a bug or something so we add a measure of insult to the implausibility.
Given that Lynn's blathering about over-work seems to have always been code for her need to keep Rod from working at all because of her need to be taken care of, I should think that we're dealing with her projecting her own feeling that being bossed and not being able to do whatever whenever by someone who wants her to suffer or whatever onto him because of her inability to realize that people might actually like working. Having her understand that people actually look forward to getting up and doing things is as difficult as making her understand people working towards a long-term goal when it's as obvious to her that not being instantly good at something is bad and wrong or whatever.