There is a nice subversion during the slaver wasp attack on Castle Wulfenbach. The Jägers, who have spent pretty much all their screentime before then needling the Lackya, immediately belt up and get to work when they realise they have a real action on their hands.
Agatha actively helps the renegade Mad Scientists of Britain summon an Eldritch Abomination due to scientific curiosity, which would be bad enough if said renegade scientists weren't already making active attempts to kill her and her friends.
Later, The Will Of Magic has this to say about why a scenario where anybody trying to cast a spell caused "massive storms of chaos magic".
Human Seer: That sounds Bad. Magic: Yes, people would stop using magic.
The Packrat: Packrat lives and breathes this trope. He sells his $2000 high-end Korg Triton workstation and then buys a vintage ARP 2600 with only one voice and no memory for $3000. He'd rather twist the knobs on a synth than those on his wife. He buys an anniversary edition Nord Lead just for the reverse keys and not for the sound. Only three of many examples.
Jareth in Roommates has his priorities straight: first his fun and clothing then his friends and love interest, everything else (like ruling his kingdom) comes later and mortal danger is somewhere at the bottom of the list. So what is his first question when appearing in a fantasy dreamworld where a mountain sized talking (eastern)dragon greets him? "Why am I in armor?" of course.
Homestuck pop quiz: A massive forest fire is threatening your home, your friend is about to get hit by a meteor, and you're the only one who can save him via the reality-warping computer game. What do you do?
A tribe of orcs kidnap Lien the paladin and steal Elan's puppet, Banjo the Clown. Elan considers retrieving Banjo to be the higher priority.
Elan: We won't leave one of our own behind again! Durkon: Ye ARE talkin' aboot rescuin' Lien, right? Elan: We won't leave TWO of our own behind again!
Nale is accused of this by Tarquin; specifically, Nale's over-inflated opinion of himself means he thinks letting everyone know that he has triumphed is more important that the triumph itself, causing him to jeopardise several plans where success hinged on him being able to keep a low profile.
The student in Priorities deliberately fails a class so the grades on their report card are in alphabetical order.
In Fixed Width, after a night of passion Rob chooses to send Emily a message saying "definitely just sex" instead of "I love you" because the line lengths in their conversation have been syncing perfectly up to that point, and he doesn't want to spoil the pattern.