So there are lots of reasons not to open. But there's one good reason to throw caution to the wind and let her rip: When someone gives you a gift, it's nice to open it. The gift giver gets to see the joy on your face, and you get to thank her in person. This pleasurable exchange may make it worth risking an occasional look of disappointment or outright bad manners.

Ed Popielarczyk, a magician and balloon artist in Florence, MA, who performs at six to ten children's parties a week, swears he "doesn't see any downside to opening gifts at a party. I've never seen a guest act particularly jealous or a birthday child act ungrateful."

Clearly, Ed brings out the best in kids (or vice versa). But at a recent party, he witnessed an act of grace so spontaneous and natural that only a 4-year-old could pull it off. The birthday boy opened a gift of a toy he already owned, normally grounds for major groans. "Yes!" exclaimed the boy. "I wanted another one of these!" His buddy was happy he liked his present, and everyone, including the adults, got a surprise lesson in how to give and receive.

Trisha Thompson is a contributing editor to PARENTING and a former editor-in-chief of BabyTalk.