Inbox shows 2 emails but nothing is there when viewing my email folders (inbox, sent, trash etc.) it shows I have 2 emails in my inbox, when in fact there are none.  When a new email come in it shows three, but there is only one.  What gives?
Try searching in:inbox is:unread.

Just input this in search bar. This means "in the inbox search for unread mail".
If you want let's say change from inbox to sent, it would be in:sent is:unread