Fresh peas are sweet and delicious served on their own with just a little butter but if the peas are moist when the butter is added it will have a tendency to just run off the surface of the peas. If you cook peas by steaming, boiling or in the microwave they are exposed to moisture. That moisture makes it harder for the butter to adhere to the peas so tossing them in the hot skillet will dry the surface and allow the butter to coat the surface of the peas. Check out our All About Peas
article to find more information on fresh peas, along with dried peas. Here you will find information on preparing and cooking different types of peas.