When society accepts girls doing 'boyish things' like liking cars, or being into sports or whatever the patriarchy decided they were into--but doesn't accept boys being into 'girlish' things like shopping for clothes, or wearing skirts (Who made these gender conforming ideals?) it sends the message that girls are allowed to be like boys because it's better.
Not only is that complete and utter rubbish because we shouldn't conform people by the gender they choose (and gender isn't simply binary--but it a wonderful, colourful spectrum), but also there is nothing in these activities that should prevent ANYONE from doing it.
As long as you're not hurting anyone in any way (including yourselves, don't do dumb things kids) you should to do whatever you want.
When I was a kid, I used to love pink. But then things changed as I grew up--pink is such a 'girly colour. What does that mean? Who the hell looked at the colour wheel and went well, this seems like a colour that indicates whoever likes this is shallow and obsessed about superficial things. (Let's be honest, that's what society has conditioned us to think about 'girlyness')
I wish I could go tell my younger self that it's okay to like a colour, and it's okay not to--but it should be my choice and no one else's.
It's so stupid--making sure people fit into boxes. There is a difference in choosing a box and being stuffed into it.
Love, respect and consent for must be taught to everyone.
Being 'girly' shouldn't be something to be ashamed of.
Be a man shouldn't mean be strong and emotionless.
You fight/throw/act/etc. like a girl shouldn't mean weakness.
Genders shouldn't constrain and conform us the way they are. They're not inherently like that--society has simply placed it on us.
I just hope that we can strive for a future in which no one is forced to be and act like someone they're not--and exist freely and if they wish, loudly.