Melt butter in a saucepan over medium-low heat; add garlic, and sauté until tender. Remove garlic from saucepan, and set aside.
Prepare mashed potatoes and milk in saucepan according to package directions, stirring with a wire whisk. Stir in garlic mixture, salt, and pepper. Let stand 5 minutes. Serve immediately.
For Chive Mashed Potatoes: Omit butter and garlic; stir in 1 (8-ounce) container soft cream cheese and 2 tablespoons frozen chopped chives.