Our receptionist at work, Barb, was shopping at Winner's last night when she noticed a couple of kids who caught her attention.
Clearly brothers, the youngest, about 7, was marching up the aisle with a boxed toy in his steely grip and a look of determination on his face. His older brother, about 12 years old, was skedaddelling up behind him, saying "she's not going to buy that for you, you know, mom's not going to get that, you should put that back, she's not going to get it" in a snotty, older brother kind of tone.
Wherein the younger brother stopped, turned around most purposefully and firmly said to his brother: "Why don't you just f*** off". And then continued on his merry way.
And that is probably their entire relationship, for the rest of their lives, right there.