I can totally relate with this kind of situation.
Even though i have only seen seher in mushk before fairy tale i somehow ended up watching her iv with Rabia some times back and she speaks really well. it's interesting to listen to her talk.
I don't really like her acting much but i like her offscreen after that iv.
For me, the actors I like fall into 3 categories.
First, I like them because of their acting.
Second, I like them because of their looks.
Third, I like them because of their personality.
Of course, one can be in more than one categories.
As for Sehar, I neither liked nor disliked her acting. But then, I rarely watch Geo dramas so I saw her only in Mushk and she was fine in that role. However, Fairy tale's case is different. She is shining in this role as she's playing herself. All credit goes to perfect casting. I must say, if the casting is perfect 90% work is already done.