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.
Ensemble Darkhorse: Despite being plain, Kurumi sure has a quite the fanbase because of her sexiness.
Fetish Fuel: Like the fanservice, explicitly identified and mocked at times.
Les Yay: Done quite a few times. One including Behoimi and Media moving around behind a curtain with some rather suggestive dialogue while they disarm a bomb. Also in episode 15, where Becky tells Sayaka to do something to keep Himeko from jumping out the back of a bus teetering on the edge of a cliff (long story) and her answer to the problem is...well, this.◊
Again with Behoimi and Media in the final episode when they swap outfits, and Behoimi admits she's a little turned on when Media shows it off.
Despite Sayaka teasing with Himeko and Miyako in episodes 15 and 17, respectively, there's actually more subtext between her and Kurumi. They even tease each other every once in a while (Kurumi usually becomes a Deadpan Snarker when it comes to Sayaka's naiveness and Sayaka even teases her, too).
Someone must have caught attention of this, because Kurumi and Sayaka are Happily Married to each other in their Twitter accounts, and they don't just love each other, it goes to Tastes Like Diabetes levels of lovey-doveyness.
Himeko towards Rebecca.
Moe: Subverted by Kurumi, who actually works at a Moe cafe. Well, it would've been a Moe cafe... if it weren't for Kurumi's lack of "moe factor". Otome, too.
The cafe itself isn't really Moe Cafe-ish anyway, what with not only the inside but the owner himself being in stark black and white.