I could not access a page as administrator user I just had a problem where a page created with a custom module caused an access denied error even when logged in as administrator user.

function cmis_play_menu() {
  $items['cmis_play'] = array(
    'title' =&gt; 'cmis_play',
    'page callback' =&gt; 'cmis_play_page',
  );

  return $items;
}

function cmis_play_page() {
  return 'boot';
}


I checked the following.


The administrator user has all the privileges
Cookies are disabled in settings.php
The database username and password are correct


I tried the following (without success):


Drush CC all
Truncating the session table
Accessing the page as a guest and as non administrator (but authenticated) user


I solved the problem by adding the following line:

$items['cmis_play'] = array(
  'access arguments' =&gt; array('administer news feeds'),
);


Why did I need to do this? 
How do I configure Drupal so that expressly setting access permissions for a page is not needed?
From hook_menu():


  "access callback": Defaults to user_access() unless a value is inherited from the parent menu item; only MENU_DEFAULT_LOCAL_TASK items can inherit access callbacks. To use the user_access() default callback, you must specify the permission to check as 'access arguments'


Emphasis mine.

So if you don't provide an access callback explicitly, user_access() is used, which, unless you're logged in as user 1 which is a special case, returns FALSE if you don't provide it with any access arguments. That's why passing in access arguments fixed it.

You can't change this default behaviour without changing core Drupal files. Being explicit about your access is better than being implicit anyway - default should always be to deny.