Ignore may be too strong a word. Best careers lists, which announce the occupations that are projected to grow the fastest or have more job openings than any other, have some value when it comes to choosing a career. You can find occupations on them that you may have never otherwise considered or even knew about. However if you depend too heavily on these lists, you could end up in a career that is all wrong for you. Worse, the bright future that is predicted for an occupation can dim since the labor statistics on which these lists are based are not stable. They are based on trends which can go off course. Job growth for an occupation may slow down and employment opportunities may not be as good as expected.
While it's important to pay attention to employment outlook when you are choosing a career—it will help minimize your chance of ending up in one that has limited opportunities—you can look beyond the "top 10" and try to find a career that is both a good match for you and has a good future. If you are set on picking an occupation from a best careers list, make sure to learn what you can about it. Read a job description and see if you find the work appealing. Interview people who work in that field to get the "real" scoop. Learn about the educational requirements and decide if you are willing to fulfill them. This is an important decision that deserves more attention than just picking an option off a list.