Little sisters turn from tomboys into badass women -- so while we want to be spoiled and enjoy every moment, we don't seek the fulfillment of those things materially. Our brothers were always there to protect us, and along the way we learned to really protect ourselves emotionally. So once we let you in and show vulnerability, that's how you know we're truly invested. When we play, we play hard. The same is true for love.
Our older brothers probably won't like you... at first
Older brothers are girls' first friends. But they're also father figures. So naturally, their instincts are to judge (or punch) first, and ask questions later. Gentlemen callers, be wary! You don't want to come across like a kiss-ass, nor do you want to seem too aloof. And for goodness sake, DO NOT try to act all buddy-buddy when you meet the brother for the first time. If you really want to attract his (positive) attention, be sure to dote on me (without excessive PDA) in front of him.
We understand (and can differentiate) boys vs. men
Having an older brother around makes the dating arena a lot less intimidating because he teaches us how to play the game. While a big brother’s advice can't prevent inevitable heartbreak, it can certainly help us navigate any situation. We learn early to define what we want in a partner, go after it, and not tolerate BS.