Restaurants And Dessert
Restaurants pay staff, rent, heat, light, insurance, etc. Doubling the food adds minimal extra cost. Larger portions give better value, make full stomachs quicker, and may reduce fixed costs-per-meal by hastening departure of guests who eat till full.
Eat less and take the extra home for another day. Take a half hour pause before committing to dessert—try walking to a different restaurant or waiting till you get home.