These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Tear Jerker: As usual, anything involving the Vulcan/Romulan sundering, particularly in Catalyst of Sorrows:
"Was the silence absolute, or did their ships sometimes...pass in the night? And if, when Romulus and Earth were at war and the Vulcans hung their heads and said "we don't know who these people are", was it at least partly true?"
The death of Hadlo, and also that of Bennek in Day of the Vipers. The former in particular: