I'm annoyed by how it invents flashback scenes for the sole purpose of solving this week's mini-crisis. Someone says a keyword, Frieren "remembers" Himmel saying the same keyword, and then repeating his conclusion verbatim in the present. That's not clever story telling, that's just retconning with style. I've counted no less than 4-5 chapters where the answer to their question "why are we helping these people?" is "that's what Himmel would have done." Why do they constantly ask this question? What did we learn about them, or about Himmel, by repeating this shtick?
I want to like this thing. I like high concept premises, I like fantasy, I like SOL... but Frieren frustrates me.