One word: Tsundere. I for some reason enjoyed it on my first watch, but on a Christmas rewatch (as you do, for that show), I realised how much I hate Tagia. Kiss x Sis is high because it was funny, but only the OVA did that. As rom-com's go, after the first few episodes, it's okay, but I rate based on enjoyment (clearly) and that stuck with me.
@marcelinaa Harem/Generic Rom-Com?