So does "salad days" have a somewhat negative nuance in it, when someone says "you're in your salad days"?

Native speaker’s answer
Rebecca
I guess it could, depending on the context! If someone said it in a way that refers to one living carefree and in their youth, it could be considered positive. But if they're suggesting they're ignorant due to their age and innocence, then it could be negative. Ex: He's obviously in his salad days and doesn't know what he's doing. Ex: Let the kids enjoy themselves. They're in their salad days.