1) ...Because we're not psychic and cannot foresee everything that will happen to us. In other words, we're not able to eat every specific food item at every meal EVERYDAY.
2) ...Because we're not able to purchase food items in the required amounts. For example, we cannot go to the grocery store and come home with 2 Tbsp of Peanut Butter, 3 cups of Oatmeal, 1/4 cup of Cottage Cheese, 10 almonds, 2 sticks of String Cheese and 4 oz of Turkey Meat for the week.
3) ...Because we're usually tempted to overeat due to the multiple numbers of servings that come in a box or container of "healthy foods." (See #2) This leads to the inevitable "Eat the whole box, start diet tomorrow" attitude.
4) ...Because some of us are not comfortable with giving very specific orders at restaurants like "Dressing on the side, no cheese, no bacon, basically nothing but lettuce, please" or "Chicken Sandwich, but with boiled chicken, no oil, no salt, no mayo, no sauce of any type, just dry with lettuce and tomatoes, please."
5) ...Because Fast Food is an essential part of America and Fast Food Salads are just gross.
6) ...Because most of us can't even remember to write our moms a birthday card, let alone write down EVERYTHING that we eat in a Food Journal.
7) ...Because most of us have JOBS and don't have time to make the "Simple Recipes" that actually take a lot longer to make. Even 30-min Meals are sometimes too time-consuming after a 9-hour work day!
8) And lastly...Because we're "Normal People" and not soldiers who are used to rations and strict guidelines. We enjoy socializing around meals, chatting around a bottle of wine, and exchanging presents while nibbling on desserts. Life is too short to let a piece of paper determine how we should live and how we should EAT!
Therefore, the best Diet Plan can be described here. (Brought to you be hi'ya bunny!)