A duty, from the Webster's New Collegiate Dictionary, is an assigned service; conduct due to parents and superiors. An obligation, also from the Webster's New Collegiate Dictionary, is a duty imposed legally or socially; a thing that one is bound to do by contract, promise, moral responsibility.
To me, an obligation is something you are obliged to do. It is a responsibility. Something a person is bound to do a commitment or a requirement. In an obligation, there is no room for a choice, although choosing not to take responsibility can result in poor consequence. Obligations are things you are forced to do, even though you may not want to do them. For example, paying rent is an obligation. It is forced and must be done, or your consequence could result in being evicted. .
A duty on the other hand, is an act of responsibility a task, but not necessarily forced. Once you promise someone you will do something, it is your responsibility, duty, to show your effort and stick to what you promise. There will always be a choice in a duty. For example, it is my duty to keep my room clean, even though I am not made to do it. It is a choice.
As I was talking with people, a few mentioned some of the things they thought were considered as duty and obligation. One person used our country and the President as an illustration. It was stated that it was an obligation for a president to be aware of what is going on in the country to make sure he is on top of everything. And his duty is responsibility to look at everything with and equal eye, and think it through with concentration. For me, it is my obligation to attend school and all of my classes, but my duty is to be attentive and cooperative. Also it would be an obligation to pay my car notes, and my duty, to keep it in respectable shape.
There is no doubt a difference between the two, and people sometimes get confused as to which one is which.
