That’s not it, you can customize/teach your Gmail by adding filters to mark certain messages as important (for example, from your boss or your spouse).
Give it a try, by enabling it from Gmail Options, and save loads of time.
Note: As this is an automated process (through algorithm) of marking your emails as important or otherwise un-important, hence there are chances that system may mark emails incorrectly at times. So make sure you don’t miss any non-important emails as well, just like we check our SPAM email once in a while to make sure that we aren’t missing anything important.
Watch following video to well understand the concept of Gmail Priority Inbox