Deliberate Values Dissonance: Dr. Raczinska, the Polish veterinarian who comes to Skeldale to look after the practice while James and Siegfried are at war, is a woman. The men are surprised to see a female vet, though to their credit, their reactions are not negative. (This may have been culturally bound, as Dr. Raczinska questioned if there were not female vets in Britain and seems surprised when Siegfried tells her there were three female students total in his graduating class in vet school.) Today, and possibly by the time the series came out in the 1970s, the veterinary line, and indeed biology as a whole, is dominated by women, so if anything our protagonists are in the minority as male vets.
"Funny Aneurysm" Moment: Siegfried delivers a lecture on the evils of smoking to Tristan, shouting that he will smoke himself to death. Brian Sinclair, the inspiration for Tristan, died of lung cancer in 1988.
Tear Jerker: Most instances where an animal dies or has to be put down. Notable instances include a horse whose elderly owner has known him most of his life, a couple whose ailing dog is the only thing holding their shattered marriage together, and an absolutely vile man who cries when his cat dies because it was the only thing that loved him.
The Woobie: Life can be awfully cruel to James sometimes.