A girl or woman who thinks very highly of themselves and thinks that women who don't live their lives exactly how they do "lesser" than them.
They may feel this way because they wear more conservative clothing, such as hoodies, T-shirts, and jeans, while other women put an actual effort into their appearance; they may not be very sexually active, and they believe that makes them "cleaner" or "nicer" than someone who has had a few partners; they might not party, drink, or do drugs, and they believe any girl who does is a cheap, alcoholic, drug-addict; they may see people who get worse grades than them as stupid; they may consider themselves better than someone for knowing useless things; they might pride themselves for being able to get through a situation in a different way than someone else.
Girls with a Taylor Swift complex tend to whine over past relationships for mundane issues - such as the ex-boyfriend saying he would be with them forever, or that he said he loved them. They never take anything they did into account for the break up, and they often push problems with their ex(es) onto their new boyfriends (comparisons, "he said that too", etc.).
One may exhibit more or less symptoms than listed, and although most Taylor Swift complexes belong to women, men can also have this disgusting egoistical issue.
Maddy: I'm sick of seeing girls in shorts, what a bunch of sluts. If they had any self respect they would wear long jeans, like me.
Maddy: No, I don't drink, sorry if I actually care about my health.
Maddy: Wow... you don't know what vertical farming is? Are you stupid? Look it up, it isn't hard.
Maddy: You had a death in the family? When my dad died, I didn't even cry. It's not a big deal, grow up.
Maddy: My ex-boyfriend said he loved me, and now you are too! That mean you'll turn out to be like him!
Everyone else: Shut the fuck up Maddy, no one wants to hear your Taylor Swift complex crap.