I gave a talk last year at Ohio University where one of the main points I was making relied on one's ability to perceive the obvious as something that will get you through your career. It turns out that's too subjective.
Common sense is so completely uncommon that it has become tiring to question why we don't see enough of it. A lot of this stems from people not having patience to sit and think critically about a problem or scenario, or even, god willing, open Google and search for a solution. None of us really know what we are doing, but if you exhibit common sense you have a better means of arriving at an appropriate solution.
Don't jump to asking someone else for their approach or their answer to a question. Sit back, breathe, evaluate the situation yourself and go from their first. The more you do this, the more you will see just how much common sense you really have.