Spawning browser windows without standard toolbars etc. In my view these features of controlling a new window's size or tool bars presence, should be given some control of the user.
Most browsers respect scripts as if the author of the documents decides the settings of the browser.
This is unacceptable. Opera doesn't have tool bars for every window, but one tool bar that applies to the window that has the user's focus. Therefore it actually allows the user to override the arrogant autrhor's decision to have no tool bars. In my view user agents should give user much more control of these features.