A 2,500 calorie diet may actually be difficult for some people to achieve, especially when the majority of food selections come from minimally processed, whole foods. Diets consisting of 2,500 calories or more are typically used by those with physically demanding jobs and/or those regularly engaging in high intensity training, cycling, running, team sports, etc.
When eating at a target of 2,500+ calories per day, you have more flexibility in discretionary food selections. This means that assuming the bulk of your daily food intake was from whole, minimally processed, nutrient-dense foods, you can have that small scoop of ice cream piece of cake, or extra serving of pasta with dinner while still remaining within your daily calorie target. When you focus on primarily high-quality food selections, you will ensure you are getting all the micronutrients you need for general health. When eating in a lower calorie range, you have less discretionary calories if you are aiming to ensure you meet your daily micronutrient needs.
Simply take a look at the 2,000 calorie sample meal plan, understanding that you could add in an additional 500+ calories through various means. If you are a snacker, you can see how you would have a bit more freedom to enjoy a couple extra pieces of fruit throughout the day, an extra serving at dinner, or maybe a cookie at the office.