The 10 worst jobs of 2010 require varying levels of training and some, such as Mail Carrier, offer better job security than most, but each has at least one significant detriment – whether it's extreme physical exertion, high risk of injury, low salary or lack of advancement opportunity. And while there will be some people for whom these jobs are ideal, each year Jobs Rated researchers try to find the careers that are likely to provide a positive experience for a majority of employees, not just a select few. So if you're a job seeker who seeks a career that pays the most, has the best prospects and doesn't risk life and limb, avoid one of these 10 jobs: