Question

off course vs obviously

Answer 1

off course means why not and obviously means exactly

Answer 2

If you want to be abrupt and a little bit rude, then go with obviously because that usually makes another person feel stupid. As in to say that they should have known the answer to that themselves because it was so 'obvious.' As for of course, it's a little more friendlier because you agree with whatever it is that they are saying because they have said something correctly and your response to let them know that would be 'of course.' It also depends on the situation and what is being said, but that's the main way that it's usually said.