Different openings can move the queen out at different times and sometimes it is okay. The problem with bringing the queen out so early is that you aren't usually sure it "belongs" on that square. Usually, you'll be better off developing your knights and bishops and castling and then the queen is the last piece to develop so that you "connect the rooks." This is a generic guideline though; it isn't a rule to follow blindly.
Here's a video of mine which might help give you a little insight on how one side may choose to exploit the queen developing too early:
When should moving the Queen start?