versus

Tonight Willa wept because I asked her to go upstairs and get her Frog and Toad anthology so Jim could read Henry a story from it. They've been making their way through the book; I didn't know that when I brought it to her room.
She cried, and pouted, and flung herself to the floor, wailing, "I wanted to read it tonight."
She only has about 80 other books in her shelves.
By the time she brushed her teeth, and we brushed her hair, Jim and Henry were done with the book, I handed it to her, asking her to take it up.
She and I went to her room. She happily jumped into bed. I asked her where the book was. She said, "um... I think I left it downstairs. That's okay, we can read something else."

These two have hit the rivalry stage hard. They argue over everything: parental affection, who gets to walk out the front door first, who gets the red cup, who likes Arlo more... it's exhausting.
On the other hand, when they're buddies, watching them hug and giggle and actively appreciate each other makes it all worth it.