Problem: The but-they-only-just-started-to-play meltdown

Sign of troubles: A tantrum—or crying, whining, and clingy behavior.

Possible causes: Fatigue, hunger, overstimulation, or frustration, or an unresolved issue that has nothing to do with the playdate.

Your move: Cut your losses. Separate the kids and end the playdate early. Leave kids with a happy memory of a half hour of fun and camaraderie. If the youngsters seem to like each other, reschedule.

Problem: The I-changed-my-mind, make-him-go-home fiasco

Signs of trouble: Child has no interest in taking turns or sharing. He hoards his toys. He tells his friend to leave or ignores his buddy.

Possible cause: Youngster is going through a perfectly normal developmental stage during which his favorite words are “It’s mine!”

Your move: Stash everything your child is not interested in sharing. Set out toys and games that have enough parts or pieces for both kids to play with—blocks, for example. Or switch the venue to someplace neutral. Go outside. Encourage kids to swing, climb, slide, or make mud pies.

Problem: The I-thought-they had-more-in-common failure

Sign of trouble: Play comes to a dead stop in a matter of minutes. Both kids look bored—or puzzled.

Possible cause: Kids have nothing in common.

Your move: Next time, ask your child’s teacher or child care provider whether the kids are well matched and whether they play together. If the answer is no, ask her to recommend a classmate who would be more compatible.

Problem: The two’s company, three’s a crowd miscalculation

Sign of trouble: Two-thirds of the participants are happy. Yours isn’t one of them.

Possible cause: It’s just plain hard for three kids to figure out how to divide equally, share, take turns, or form a consensus.

Your move: Discourage free play. Instead, provide a project each child can work on individually—such as coloring, painting, or stringing pasta or beads.

And next time, stick with a 1:1 ratio or even numbers of playmates