You got her name because her parents thought that they were getting a son (“You” can be used for both males and females). The exact origin of the name is a combination of the phrase that Mrs. Watanabe associates the most with her husband (“yousoro”, which would later on become You’s own catchphrase) and the term that Captain Watanabe associates the most with his wife (the kanji for You’s name is associated with “sun”, “glorious”, “bright”, etc.).
You’s dad was actually a little disappointed when he found out that You was a girl, because he had hopes of going on father-son adventures with his firstborn. Then baby You’s first word turned out to be “Papa”, and he instantly fell in love. You also grew up to be quite the tomboy, so You’s dad ended up having adventures with his firstborn anyway, with the added bonus of having a daughter who looked really cute in a sailor uniform.
Captain Watanabe taught You self-defense techniques because no way in hell are any perverts gonna have their way with his precious daughter!!! He made sure that she could even fight back against someone as large as him (a fully-grown muscular man), so it’s no wonder that You easily overpowered Mari in Episode 11.
You’s dad is a fantastic cook - especially when he’s drunk. He’ll get very odd cravings which, when combined with his drunken state, leads to strange but delicious new recipes. You has a very good sense of smell (*sniff sniff* a uniform!) so no matter what god-awful hour it is in the night, she’ll wake up when her dad starts cooking. Over the years, she’s picked up a lot of his techniques. This is why You was able to improvise a dish from Mari’s Stewshine and Yohane’s Tears of a Fallen Angel in Episode 10.
Mrs. Watanabe is actually terrible at household chores. You loves salisbury steak because it’s one of the few dishes that her mom can make without creating an utter disaster. You knows her dad’s curry recipe by heart because she learned it at a very young age out of desperation. She’s pretty much in charge of doing the sewing when Captain Watanabe needs his uniforms fixed as well.
You tends to bicker a lot with her mom, since Mrs. Watanabe is the stricter parent (out of necessity: Captain Watanabe is gone most of the time due to his job as a ferry captain, so he endlessly spoils You in the rare moments that he’s home). Mrs. Watanabe is the classic “screams-when-she’s-angry” type, while You, of course, takes after her dad and gets very quiet and withdrawn when she’s upset. Their fights tend to be about minor things though (e.g. staying up late, sub-par test scores), so they’re usually resolved pretty quickly and the two will be back to normal after a day or so.
You inherited her wavy hair and sunny disposition from her mom. When she was younger, Mrs. Watanabe was very self-conscious about how frizzy her hair would get whenever it was rainy or humid, and used to be bullied because of it. Then one day, the stoic boy who sat in the back of the classroom suddenly walked up to her and said, in a quiet but deep voice, “I think your hair is beautiful, so please don’t let it keep you from showing that bright smile of yours.” No one dared to tease her again after that.
Even though that was years ago, Mrs. Watanabe is still a little sensitive about her hair. When she found out that she passed along this trait to her daughter, she made sure to keep You’s hair short because she didn’t want her daughter to go through the same thing. Luckily, You didn’t mind since she preferred having short hair for practical reasons (i.e. easier to manage when swimming).
If you couldn’t tell from that clichéd-sounding romantic line before, You picked up her charms from her dad. They’re both naturals when it comes to making girls swoon.
You’s dad and mom were each other’s first love (You’s dad was a bit of a playboy so he dated a number of girls, but You’s mom was the first person he truly loved) and their story is basically straight out of a shoujo manga: happy-go-lucky heroine falls for the strong-and-silent boy who will do anything to protect her.
You’s parents started dating in high school, but had to separate for a few years because You’s dad went to work aboard a ship in order to gain experience for becoming a captain. Before he left, he told You’s mom, “No matter where I go, my heart will always be with you, so…will you wait for me?” and then bent down on one knee and reached into his pocket to pull out a small box and oh god I’m grossing myself out with the amount of cheese here so I’m just gonna stop lol.
Later on, when You’s parents find out that their daughter is gay, Mrs. Watanabe smacks her husband and tells him, “See, this is all your fault for being so overprotective! Since you insisted on sending her to girls’ schools and kept threatening to kill any boys that got close to her, you’ve turned her into a skirt-chaser. Just look at your daughter’s shameless flirting with her 17 girlfriends, goddamn it!”
You’s dad is very conflicted about this. On the one hand, he had always been lowkey worried that You would fall for some cocky sailor boy because of her obsession with uniforms, so he’s glad that this nightmare will never come true. On the other hand, he now fears that one day his daughter will get lynched by the fathers of the countless girls who’ve fallen under the Watanabae spell.
The next father-daughter late-night cooking session has Captain Watanabe awkwardly clearing his throat and saying, “Look, you know I’ll always support you…so if you ever want any advice on dating girls and, er…other things…I’m here for you…”
You contemplates taking her dad’s shot glass and chugging down his drink because this is not a conversation that she wants to have while sober.
“…please Papa, let’s just finish frying this kiwi.”
Later on when You does drink, her cocktails of choice are things like daiquiris and mojitos and long island iced teas. Everyone is somewhat bemused by this since they’re such fruity drinks, until they remember these all have a hearty amount of rum and other hard liquors in them, and You usually gulps down glass after glass of these “girly” concoctions.
You’s personal favorite was introduced to her by Mari, and contains gin, rum, tequila, vodka, Blue Curacao liqueur, sweet and sour mix, and 7-Up. The name of this cocktail: “Adios Motherfucker”.