Microsoft MVP and Regional Director Paul Randal of SQLSkills.com fame announced on twitter...
This was a fantastic series of 30 blog posts from back in April that I'm sure corrected many DBAs misconceptions on a variety of SQL Server topics. Now all 30 days worth of posts are in .pdf format and can be found on the SQLSkills website here:
Myths and Misconceptions: 60 page PDF of blog posts
As a DBA you are responsible for the guidance and direction of your database environment. If you didn't get a chance to read these blog posts as they came out (and even if you did) I would highly recommend downloading this PDF and working through the examples provided to ensure that you really know what you think you know.
Everyone in their career has provided (at one time or another) information that is not quite true or possibly 100% totally wrong. It happens, nobody is perfect. Chances are it is because you either misunderstood the topic yourself or got this information from someone that you deemed to be a trustworthy source who just turned out to be wrong this time around. The internet and technical communities (Twitter, Blogs, Forums, etc) are a fantastic source of information but it is your professional responsibility to fully understand and test what you learn.
Big thanks to Paul Randal for the great series of posts and to Peter Maloof for putting this information into an easy to read/reference PDF document.