Samsung S3: Only retrieve "contact with number" in contact search
From my experience, GMail won't put people you have only emailed into your "My Contacts" built-in group (See Gmail and auto-adding contacts). 

Because of this, you should be able to tell android to only pull from your "My Contacts" list, which would presumably only contain  your important contacts.

The steps to do this will vary depending on your ROM. I'm using a nightly build of CM10, and these are the steps:


Open Contacts
Press Menu button, and choose "Contacts to display"
Choose "Customize" 
Choose the account of interest, and make sure only "My Contacts" is
checked/selected (Or any other groups you want).


Hopefully that helps you out, or at least gives you an idea of how to accomplish this.