So, you're an "average Joe" who is developing some type of instructional application.
Writing objectives is important to you because:
objectives provide a plan for the instructional materials you must develop
objectives provide a focus for developing the instructional strategy
objectives provide the foundation for assessing the learner's knowledge, skills, or performance
objectives provide criteria for measuring the effectiveness of the entire instructional application
objectives help direct the learner's attention to what will be expected of him/her