Snuggling under her blankets at bedtime, Ella, 3, gazed up at me and announced longingly, "I want a new mommy." Not even four years into my tenure as Mom and I was already being edged out of the job. Even worse, Ella started announcing "I want a new mom" frequently, like whenever I failed to buy her a ring pop at the grocery-store checkout. Some days, it was all I could do not to retort, "Yeah? Well, I want a new kid!"

Developing the knack to verbally push your buttons is just part of your child's linguistic and behavioral development. The challenge is to teach her to be courteous while allowing her to assert herself  -- and do it without responding like you're 3 years old. What to say (and what to skip) in response to these gems:

"Mine!"

Whatever 18-month-old Weston Congdon has, his 3-year-old brother, Addison, wants, even if it's something that's collected dust in the toy box for the past six months. "What drives me crazy is that usually it's a baby toy, like a teething ring," says their mom, Sarah, of Ames, Iowa. "I think, 'What are you gonna do with it other than take it away from your brother?'" Now Weston, a beginning talker, walks around the house repeating "Mine, mine, mine" ad nauseam. His frustrated mom has been known to retort, "Well, then, the couch is mine and you can't sit on it."

A better way to respond: As tempting as it is to give little ones a dose of their own medicine, it won't help them see the error of their ways, and it may confuse them. Yet keeping your cool in the face of "Mine!" can tax even the most Zen-minded mom.

"Ignoring the behavior is best, but even as a clinical psychologist, I can't," admits Ray Levy, Ph.D., a dad of one and the coauthor of Try and Make Me! "I'd rather have something to say in response that I can depend on." His solution: Toss out a "brain-dead phrase"  -- a short-and-sweet sound bite that lets a persistent child know he won't get his way. With a child who insists that everything is his, simply keep repeating, "Sorry" or "It's nice to want things." End of story. Even if the empty phrase doesn't completely shut down the whining, having something  -- anything  -- to say will keep you from saying something that you shouldn't.

Melody Warnick is expecting her second daughter, who will no doubt want a new mom someday, too.