I never had any strong feelings about Margaery either way. She was cute though and really knew how to play the dudes. I liked her okay, but I wasn't like a huge fan of her character.
For me, what really got to me was the look on her face when she saw her father and her father looked back at her. They looked so panicked. The whole Loras thing was sad too, when they carved his forehead. Their father's reaction was too much
Tyrell's deserved better.
So I didn't cheer when she blew up the sept. It was conflicting.