Tamara Wilson considers herself an equal-opportunity flirt. She banters playfully and purposefully with her butcher (who sharpens her knives at no extra charge), with security officials at the airport (one let her onto a flight even though she'd left her ID at home) and her female UPS driver (who now leaves the packages on the porch).

"I've used my big, blue eyes and smile to get everything I ever wanted," says Ms. Wilson, 52 and the owner of a Seattle marketing firm. "Flirting opens doors."

Flirting...