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.
YMMV: Junjou Romantica
Angel Devil Shipping: The Romantica pair, with Usagi being the 'devil' since he is very perverted and possesive towards Misaki, and Misaki being the 'angel'.
Big Lipped Alligator Moment: Miyagi, straight up until that point, suddenly grabbing a heartbroken Hiroki and trying to kiss him before Nowaki stepped in. Never showed any interest in him before, and it's never mentioned again afterwards.
Miyagi is normally pretty grabby and in other ways overly familiar with Hiroki, though. He just likes to tease his kohai.
Base Breaker: Half part of the fandom are not fond with Misaki, due to his Tsundere streak to Usagi, his obliviousness when it comes to love and his feelings and he also prone to get into troubles in almost every chapter. While the other half of the fandom loves him due to his kind-hearted and selfless personality.
The Terrorist pair also shaping to this, as one of the reason is the huge age gap of Miyagi and Shinobu.
Fan Dumb / Hate Dumb: Many of the fans believed that Misaki is a Satellite Love Interest to Usagi and ranted about everyone seems to fell in love with him despite the only people who fell in love with him so far are only Usagi, Haruhiko, Kaoruko and Ijuuin.
Fridge Horror: Misaki gets a dose of this when Usagi brings up telling his brother (Takahiro) about their relationship... and Misaki realizes the huge problems that arise with the situation that he's dating his older brother's best friend.
Probably the reason why Misaki fell in love with Usagi is because he secretly enjoyed it as Usagi was raping him during in the beginning...
Internet Backlash: In a discussion or a forum, do NOT ask which one is the best couple among Romantica, Egoist and Terrorist.