From the wording of these particular questions, you need to answer with your own personal thoughts and reasoning. For example, this morning I ate a piece of strawberry rhubarb pie. I ate it because I like sugary, sweet flavors for breakfast, and it happened to be in the refrigerator. Additionally, it didn't require any more "work" to make it other than the microwave. Yes, I am fully aware that far healthier options are available, but it came down to the pie or a brown sugar Pop Tart.
Part of your question asks what influences a person's food choice. As you can see from my example, convenience played a major role in my food choice. This is true for many Americans, and it is one reason why fast food restaurants continue to exist. Fast food restaurants provide customers with food that tastes good, can be obtained relatively quickly, and is relatively affordable.
While I openly admit that I could find "healthier" options for breakfast, I don't worry too much about it, because I understand overall dietary needs. Roughly sixty percent of a person's diet should be carbohydrate-based. Personally, my carb intake is higher than that; however, that is because I coach high school cross country, and I run four to seven miles per day. The body will first use carbohydrates for fuel, so I make sure that I "carb load" in the mornings. The remaining forty percent of a person's diet is roughly split between proteins and fats. Proteins are preferred over fats, but fats should not be ignored.
Carbohydrates, proteins, and fats are three of the nutrients that a person needs. They all have caloric intake values, so a person needs to know what their caloric intake value should be in order to calculate how many carbohydrate, protein, and fat calories they should be taking in. In a pinch, portion control can be used to estimate food intake amounts. Your hand is a good indicator. Your palm is about the same size as a deck of cards, and that is the recommended three-ounce serving of protein.
The remaining three nutrients that need to be a part of a person's diet are minerals, vitamins, and water. Vitamins help to fight off disease and are critical to overall health. Minerals have similar functions and do things like help build strong bones and teeth. Water is critical to surviving. It lubricates the body. It flushes the body of toxins and helps to carry nutrients to cells.