First of all, in my opinion, the most important reason is to gain competence to live a better life in the future. Competition of our days has become more and more drastic, and even a very simple job or low position will attract hundreds of candidates to apply for it. Only those who have a good education and general knowledge can gain better work. So, we should attend college or university for better competence.
Second, attending college or university can change our life. For example, to myself, I am a student from countryside. I am one of the few people who can attend college or university. Most of those who have not studied in college or university go to work early in a small factory in a small town or on a farm in their hometown. Just because I have taken higher education, I can get better chances to study or work in the capital of our country where a lot of people want to go to. Why? Good education gives me chances to change my life.
The third reason for attending a college is to increase knowledge. Study is a so interesting thing that it make our life rich and colorful. It expands our eyesight by informing us with lots of new things what we cannot gain from our common life or experience. On the other hand, by attending college or university, you can learn the knowledge or skill necessary for your future work. People attend college or university for various reasons. Some may attend for new experiences, and others may think about other things. What I have mentioned is just very few of them.