The sex scenes ruined the realism of the movie.
I thought that the movie was very realistic in almost all aspects (even painfully so at times if I may add) but the unrealism of the sex scenes ruined it for me just a bit. Adele's sexual encounters with her first boyfriend and then Emma were nothing short of a porn flick. I don't have problems with nudity or sexually explicit scenes at all (before anyone calls me a prude and thinks that the problem lies in that) but these ones were painful to watch for me simply because of how badly they fit in with the rest of the movie. I loved the movie as a whole but whenever a sex scene would creep up I felt like I was watching something about the sexual encounters of porn star. Those scenes didn't portray a young girl who is trying to discover herself and her sexuality - at least in my opinion.
Now, I know that there are some people out there who would probably just watch this movie for the sex scenes (sad but true) and I'm wondering if the director did this intentionally to guarantee himself a larger audience. Since he managed to depict realism so well in all other aspects, it seems doubtful that he'd be so oblivious to the lack of realism in the sex scenes.