I find that pathos is part of Roy Clarke's comedies in general. Mostly it is with the men and marriage in general usually puts them in sorrowful predicaments (Howard and Pearl, Wally and Nora, Richard Bucket in Appearances, etc.)
In addition to the previous stated characters, there is Wesley's mechanical inventions going awry as well, Howard's failed attempts to find a quiet, undisturbed setting with Marina, Smiler's general hard luck, Billy's desire to build an army, etc.
Another aspect to the show that counteracts the failed aspirations are the false sense of grandeur. There is Foggy with his military background, Seymour's educational background, Billy's ancestry, and Truly's experience at the Yard. Although there is an in control, authoritative demeanor to Truly that makes his bragging rights seem most realistic.