Navigation pane default set to display, cannot be changed.

Ugghhh... Could you please fix this in the next revision?  Looking at the forum, seems you like your navigation pane, so well that you think we should have to look at it by default everytime we open a document. I was going to ask how to set the default, but it seems someone else has asked the same question and they were told it is a good pane.  I view dozens of .pdf each day, or a hundred of them, and I do not want to have to look at the navigation pane each time or to have to go over to that sideways arrow to hide it.  No problem except I am doing this so many times in the day.  Thanks.