The Ship Tease between Lydia and Ingvar makes an awful lot of sense. Lydia is a plain, straightforward kind of gal with little patience for tomfoolery or pretension. Unlike Stig and Hal, who tried to play The Casanova for her, Ingvar never tried to be a Dogged Nice Guy. Admittedly, neither of them was really overly obnoxious, but it's notable that she's most receptive to both Hal and Stig when they're genuine, and Ingvar is always very honest and upfront with her.
Extra Fridge Brilliance: He's hinted to not have a lot of self-esteem due to his myopia, meaning that he probably didn't think he had as much of a chance with her as the athletic Stig or Hal.
All but confirmed later on.
In Book 1, Stig at first doesn't like the idea of running away from Hallasholm. Hal puts this down to Stig's aggressive personality, but later we learn that Stig's father had run away from Hallasholm after stealing from his crewmates. Stig no doubt wanted to avoid the comparisons to his father!
The evenness of Gilan's sparring match with Stig, even though Gilan's got decades more experience, makes sense when you remember that they've been on a ship for a couple of days. Gilan is probably still developing his sea legs, and is also most likely used to having more room to maneuver (a small wolfship like Heron would not give much space for footwork, as opposed to the woods, fields, and even streets where he usually fights). Stig, on the other hand, grew up on and around boats, so he's much more used to both the cramped quarters and the motion from the waves.
Erak allowing Kloof to chew on his walking stick at the end of The Stern Chase isn't just him being kind. In a warrior culture like Skandia, life debts are very important, and she did save his life from the pirate earlier in the book.
Slaves of Socorro: Hal seems shocked at the effect his sabotage had on Nightwolf. Did he merely underestimate it or did Tursgud doom the ship and the crew by trying to go from a stop to full speed?
Related to the above bit of Brilliance, after the Andomal was stolen, Stig no doubt felt that everyone would be comparing him to his dad. Also, while the Brotherband were away, Stig's mom probably had to deal with the extra ridicule of having a son and husband who were both outcasts.
