wp_page_menu not working right?

I tried your code it works perfectly fine for me, to give output as:

<div class="container_class" id="container_id">
<ul class="menu_class" id="menu_id">
   <li class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-154"><a href="http://www.ohitsfunny.com/category/funny/">Funny</a></li>
   <li class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-159"><a href="http://www.ohitsfunny.com/category/jokes-2/">Jokes</a></li>
   <li class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-156"><a href="http://www.ohitsfunny.com/category/love/">Love</a></li>
   <li class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-155"><a href="http://www.ohitsfunny.com/category/motivational/">Motivational</a></li>
   <li class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-157"><a href="http://www.ohitsfunny.com/category/political/">Political</a></li>
   <li class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-158"><a href="http://www.ohitsfunny.com/category/news/">News</a></li>
</ul>
</div>

I think you might be missing the argument ‘theme_location’, and founding no menu at that location the fallback “wp_page_menu” is being executed. Which doesn’t use the classes you mentioned in the call to “wp_nav_menu”.

In case you don’t know what a ‘theme_location’ could be:

function register_my_new_menu() {
  register_nav_menus( array(
    'custom-menu'   =>  __( 'Custom Menu', 'the-bootstrap' )
    // Theme Location: custom-menu
    // Menu Name: Custom Menu
    // Create and assign a menu to this location in Dashboard->Menus
  ) );
}
add_action( 'after_setup_theme', 'register_my_new_menu' );

Apologies, if I get to basics that you already know.