Clearly, no one expects you to know exactly what you want from your career the minute you graduate from college. But, as you gain experience, you should become more astutely aware of what your idea of "the right" job looks like. If you find yourself stuck, feeling like nothing will ever make you happy, it's time to do some self-reflection.
If you need help, download my free e-workbook "How Nourishing is Your Career?" which walks you through a process to determine what's working (and what's not) in your current career so you can begin pinpointing the things that may provide (or detract from) career fulfillment the future. The workbook is available in the Free Career Resource Library here.
Once you know more about yourself, you can be more discerning in the job search process.
The other thing prospective employers will assume is that you don't really know what you want. When you tell them why you'd be perfect for the job and why it's a position you'll be thrilled to have, they'll doubt your motives. Your past doesn't indicate that you really know what will please you. Again, with a little clever maneuvering, you can frame it in such a way that your past actually proves that you know exactly what you want—and DON'T want.
Though I agree that job hopping will gain you more experience and enhance your expertise, as an HR Specialist, we still look for a person who has tenure in his post. This will give the impression that the applicant has all the right work attitude which allows him to stay long in a company. If I see a resume with 6 employments in a couple of years, it makes me ask, what hinders the applicant from staying. Is it the company or is it the person himself.
I have had many issues with job hopping on my resume because for 10 years, I had a steady seasonal (April-October) job at a travel company that I loved and excelled in but was let go. So 'Seasonal Travel Agent' is on my resume for that time. But during the off seasons, I worked seasonal retail jobs, temped for several agencies (signed up for four to get the hours needed to pay bills) and did contract work.