I often see emails in my inbox that I know precisely what action to take without the need to open them. I might need to apply a label, move the email, type a one-word reply, or search for a different email from that user. Now everyone can easily do that right from their inbox!
While viewing your Gmail inbox, hold down the Control key and click your trackpad. (This is equivalent to a right click on a PC.)
Without opening the email, the following sub-menu will appear: