Honestly, so many things I hate in this story...
There's clearly a quality drop for cheap drama halfway through, and Sugi is literally the shittiest person I've yet to come across in a Yuri romcom... But mostly I hate the mangaka's thematic attitude towards her, refusing to reproach her and the other girls' unhealthy 'dating for dating's sake' mentality; not to mention her worldview of relationships as status symbols. Then again, this is a pretty old manga, and societal values have shifted a lot since.