Writing instructors often attack the use of the words "obvious," "of course," and the like. "If it's 'obvious,'" they mock, "then don't say it!" But giving up these words is easier said than done. I can't imagine giving an econ lecture without occasionally saying them. "Obviously, if you raise the price high enough, people won't want to buy." "In the long-run, of course, entrants will drive prices down again."
Why is it so hard to surrender these words? The main reasons: When you say "obviously," or "of course"...
1. ...listeners know not to waste time looking for a complicated rationale behind your statement. What they see is what they get.
2. ...listeners can identify your starting points. It may be obvious that X is true, and obvious that X-->Y, but if you just start with Y, people will be confused.
3. ...listeners find out what you take for granted. If it's different from what they take for granted, that's news.
Of course, "obvious" can be overused. But you should ignore anyone who tells you to stop saying that things are "obvious." Obviously.