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.
Les Yay: Enormous amounts of it, and it's not always just teasing. Akira with Mayu, Chun-Lan, and pretty much any girl; Yu-Ling with any girl; Miller with Nobuo, in volumes 6-7 Julian, from volume 11 on Sutton, and lots of random guys; Yui and Midori; from volume 12 on, Kaede and Mamoru.
Nightmare Fuel: Many flashes-backs, dreams and/or hallucinations sequences.