Not at all. It's built into the hiring system, the probational
  period. They don't care about how you can do in the BEGINNING of
  the job. They know you're not just gonna "jump in and be
  perfect". Why? Because YOU DON'T KNOW _how_ they're going to
  need you to use that knowledge, how much of it you need to know.
  "Do I know Java?" "Yes". I know the name of it. I know what it
  does. I know what's unique about it. I know what I like and
  don't like about it. Can I write something in scratch with Java?
  No. But I don't know what they need. It's not lying to say
  "yes". It may _feel like_ lying, but it's not. Now, if they
  asked, "Do you know the behaviors of Transnuclear mice with
  predefined T cell receptors?" I have to say "No". But do I know
  Java? Yes. Do I know enough for the job? No way to know even if
  I could write Java in my sleep. So, liar? No. Knowledge is
  capabilities, not answering multiple choice questions... unless
  the job has a quiz. tongue emoticon == Awesome :)* Yeah, I think
  it's the only way to get into a good job with growth potential
  for yourself. == Yes, I found giving some autobiographical
  stories of my background in similar areas to be extremely
  useful. I'm good at those, so I did well in that way. I like the
  glass of water idea. I'll be sure to add that to my mental list
  of interview tips when someone asks me "what to do". I may not
  give perfect advice, but I try to boost confidence in those who
  lack it but are capable. ==