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.
Fridge Brilliance: After Jacen kills Ailyn Vel, no one in the cast — even Jacen — remembers that she tried to kill him twice in Shards of Alderaan.
Harsher in Hindsight: Back in the New Jedi Order series, Leia had a depressing vision of Jaina and herself telling Jaina’s kids about their heroic late aunt Mara. The vision seemed to have become irrelevant when Mara recovered from her illness, then 16 years later, Jacen became Darth Caedus.
Idiot Plot: The heroes should have been able to catch on to and short circuit the villain's plot relatively quickly. It can also apply to Jacen himself, for thinking that listening to Lumiya in the first place was a good idea.
Too Many Cooks Spoil the Soup: A possible real world version, as the series grew more chaotic, padded, and just plain weird as time went on. Notably, Karen Traviss had a widely different style of writing and concept of the universe from Aaron Allston and Troy Denning, leading to the Trapped by Mountain Lions plot below, while each author also had their own subplots and interpretations of characters, each of which would radically change the context of the series.