Torikago Syndrome
The problem with shounen ai and dark/psychological manga is that there're a lot of hints or suggestive scenes, but you can't be sure what happened. For example, the incestuous relationship between Kain and his mom or his twin brother, Litch. There was scenes that would suggest Kain's mom had sex with him because his shirt were opened, but maybe she abused her son in non-sexual way. Yaoi would give more impact to this kind of tragic story, make the scene seems clearer without interpretation by the reader, like Acid Town, which obviously indicated the rape really took place, or the relationship between the twins.
Kedamono Hatsujouki!!
Kouji is such an ass, he should get it in the ass too sometime. Kouji likes Yuki (romantically) and also like Shin (as friend and sex partner), but Yuki likes Shin (romantically), and later on comes to like Kouji too (as sex partner)?
Saiaku na Rinjin
I thought uke's ex would be a girl, but it was a guy?!?
Ai No Chikara De Koi Wo Surunoda
Don't like Yukihiro at all, even hate I might say.
Risou No Koibito