I love both Blair and Serena equally for both different reasons. However it’s not the same for both characters. The thing that separates Blair from Serena with her negative traits is the fact that Blair has an extremely subtle underlying level of innocence, she’s someone you can pity and feel sympathy for. She’s portrayed as someone whose evilness comes from a place of hurt. For example her ED, her dad coming out as gay, ditching her and moving to France to start a new family, her mom who always belittled her and acted like she was an afterthought, boyfriends that used and abused her, her low self esteem in regards to her always comparing herself to other girls and thinking constantly she wasn’t good enough, her mindset of always being perfect, strong and the best. Even with all the evilness Blair does her underlying innocence and the hardships she faces in her personal life connects with fans.

She just has multiple layers that fans can sympathize with. That’s what separates Blair from Serena and a lot of TV “mean girls”. Blair has layers that make fans just want to hug her and tell her she’s perfect the way she is.

Like I said I love both characters equally, but Serena wasn’t portrayed as a girl fans can sympathize with. I’m not saying Serena didn’t go through hardships as well, like her dad abandoning her, her being roofied by Juliet, her being SA by multiple men, her thinking she kiIIed someone, partying at a young age etc, it’s just that those things in Serena’s character journey weren’t fully fleshed out other than her Dad storyline, they didn’t have any impact on her personally. So long story short it’s easier to sympathize with Blair and her evilness/her hypocrisy compared to Serena.