>>281457397
That's not even the issue though, some characters can just stay cool during fights, especially when it's advantageous to do so and they've been trained to act that way. Even the most autistic ones like Frieren and Fern emote all the time, but not when they're in the middle of fighting because they've drilled or actually fought for years to keep their composure for that exact moment.
Fern is visibly excited when dancing with a boy, surprised when Frieren wakes up early and easily annoyed when someone is acting retarded in front of her. Frieren gets downright giddy over rare books and potions and flustered when dealing with other people. There's a dozen examples in this thread alone and far more in the series and the manga.

The only problem here is trolls and shounentards who require constant goofy faces during fights even if a character should be prepared and controlled enough to suppress that. If Fern isn't bawling like a baby when she needs to deal with a demon, that's unrealistic because uhhhh she's just a little baby teenage girl or something. Make sure to ignore how Fern DID freeze up in shock and visibly emoted at the monster/ghost of Heiter though, because that would be really bad for the argument.