Why shouldn't microwaves be reflected by microwave cookware?

Microwave cookware is designed to allow microwaves to pass through it rather than reflect them. This is essential because microwaves cook food by agitating water molecules, generating heat. If the cookware reflected microwaves, it would prevent effective cooking and could potentially damage the microwave oven itself by causing energy buildup. Additionally, reflecting microwaves could lead to uneven cooking and hotspots in the food.