Why this query returns rows that I don't want to be there I'm trying to running this query:

SELECT * 
FROM 
    (`default_users`) 
    LEFT JOIN `default_profiles` ON `default_profiles`.`user_id` = `default_users`.`id` 
WHERE 
    `default_users`.`group_id` = '3' 
    OR `default_users`.`group_id` = '4' 
    OR `default_users`.`group_id` = '5' 
    AND `default_users`.`email` LIKE '%polar%' 
    OR `default_users`.`username` LIKE '%polar%' 
ORDER BY `default_users`.`id` DESC


But get unwanted results and don't know the cause and by unwanted results means webmaster which I think isn like %polar%. Here are some sample data for testing http://pastebin.com/Fyx0TcGY, any advice?
Yes @jon-seigel you're right and thanks for your suggestions didn't see it before :( I add some parentheses and now it works see the right query below:

SELECT * FROM (default_users) LEFT JOIN default_profiles ON
    default_profiles.user_id = default_users.id WHERE 
    (default_users.group_id = '3' OR default_users.group_id = '4' OR 
    default_users.group_id = '5') AND (default_users.email LIKE '%polar%' 
    OR default_users.username LIKE '%polar%') ORDER BY default_users.id DESC