On some webspaces the number of requests which can be performed simultaniously are limited. So some widgets on the dashboard are not loaded(only displaying "Loading widget, please wait...") until you press the reload button.
As there is often no control over server and PHP configuration this behavoiour cannot be changed easyly by the user.
So it would be nice if Piwik would automatically reload the widget if the server returns a 500 error. Maybe in the config.ini there could be added "reload_widget". The value should normally be set zero but could be increased manually, if any problems occur.
PS. I know this has been discussed very often and there may be several solutions for one single provider, but this would be a possibility to solve this problem for all users.