I switched to an all girls school for 3rd grade, and stayed there until I graduated high school, which was utterly fantastic for self confidence and had teachers and staff that understood how to deal with more than one type of child. I wasn't pushed to be more expressive, warmer, or more effusive because that's how adults like little girls to be. I was allowed to warm up to people at my own pace, even if that meant I was never open with everyone. Being allowed to have boundaries is important. I actually think my school being all girls was beneficial from the start, if only because most schools aren't staffed by feminists, so we didn't get nearly the same amount of crappy early socialization (also, I got to do a major project in 4th grade on Elizabeth Cady Stanton. We were always encouraged to pay attention to notable women, like Marie Curie and Amelia Earhart). It's probably even more important for teenagers though, because I could see a lot of the benefits of early single gender education being reversed by later coed education. I noticed in high school that girls from my school did much better than girls from similarly good coed schools. We had higher participation and more success with nearly any academic competition, but particularly things involving either STEM or public speaking, and generally had records similar to the boys from coed schools with similar reputations.

My mom is certainly a feminist (and not a lib fem, although she's milder than rad fems generally are), and while she did encourage us to be kind, she never taught us that it meant prioritizing other people over yourself (like, with the pizza example in the article: why should you be the person to give up your preferred type? If someone really detests one type and you have a mild preference, then it makes sense, sure, but usually it's more fair to each have half a slice of each type, or alternate who gets first pick. Giving up something you want for someone else isn't a matter of basic kindness, but rather doing someone else a favor. Which is important, but its place is more in building interpersonal relationships). She's seen too many women erase themselves to ever encourage that. For her, it was more about being a good person.

One thing my mother did emphasize that I think usually is ignored for girls is courage. She's always encouraged me to be courageous, particularly morally. I'm sure this has helped me stand up for myself, but it also helps me stand up for others, which is a very meaningful form of kindness. I have a habit of getting between the bullied and their victims. When I was little and lacked finesse, this was a problem (it led to me getting bullied quite badly, and the school refused to deal with it, so I switched schools to the all girls one. Ultimately a very good thing), but over time, I learned what worked and what didn't, which is really a very useful thing to know. I know adults used to tell me how bullies would stop if you didn't react, but this is completely false, and only contributes to victims trying to erase themselves. You can avoid becoming a target that way, yes (useful if you have a psychotic boss and aren't yet his punching bag), but it usually causes a bully who's already focused to escalate, in hopes of making you break down. What is effective, if very much not a "nice" thing to do, is humiliating them. My sister attracts bullies because her style is a bit alternative, but people rarely make the mistake of trying twice - she'll laugh in their faces and say that it's an honor to be disliked by them. Deterring a bully from going after someone else requires being somewhat nastier.

Obviously, to avoid being a bit of an awful person yourself, it is important to understand when to retaliate. A rude retail worker probably is just having an awful day. Same with people who are kind of snappy. And you being rude back is never going to help that. Being polite is usually appropriate. But there's other times when it's a pattern of behavior, and then it's usually about dominance and feeling superior. This is fairly obvious when it comes to bullies in school, and not difficult to figure out when it comes to, say, street harassment. And the correct way of dealing with that (unless you fear for your physical safety) is to take control from them and force them to feel small.