How to find un-read emails that are hidden under stacks and stacks of read emails?
Simple, just add is:unread to your search then Gmail will bring all unread emails relevant to your search.
For example, if you want to see all unread emails from your Friends circle:
Usually you would use circle:friends in the search box. To get the unread ones, add is:unread to it.
This will bring unread emails from your friends in the chronological order.
Some other examples :
“john is:unread” – this would bring all unread emails that have the word “john” in its subject or body.
In very simple words, just add the phrase is:unread to any search query and it will bring ONLY the unread email to you.