Given the number of developers I've seen who list SQL as "expert" and can't write a simple JOIN, or actually cannot complete the FizzBuzz challenge. As an example, I've been a pretty big fan of JS for a long time (since well before 'The Good Parts'), and after "AJAX" became the next big thing, wound up on an interview panel, and man, the number or developers putting "Expert" on their resumes who didn't even know some fundamentals were staggering.

Maybe it's just me, but when someone uses the term expert, I tend to be doubly suspicious. Especially if they use that for more than one or two skillsets.