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.
Awesome Music / Ear Worm — The openings to both seasons are incredibly catchy and cool-sounding, especially that of season two.
Creator's Pet — Matsuoka is revealed to be this. In fact, she has started appearing more in the manga due to it.
Fridge Brilliance — In the first episode of season 2 (a full episode of Gachiranger, occasionally cutting back to Hitoha), Gachi Pink at one point needs to take the wheel of a bus, and the scene immediately switches to an exterior shot of the bus swerving wildly. In this shot, Gachi Pink suddenly looks completely different from before. Your first instinct would be to think that the animators got lazy and took a shortcut, but then you remember that Gachiranger is a Toku show, and therefore would be live-action in-universe. It wasn't bad animation, it was a stunt driver.
The rivalry between Mitsuba and Miku is filled with so much subtext that you don't even need yuri goggles to see it. Miku's habit of constantly taking pictures of Mitsuba (supposedly so she can use them for blackmail) doesn't help.
Miyashita's almost obsessive attempts to befriend Hitoha occasionally come off as this.