The link below shows an example of security going horribly wrong. This is an example of someone going through the process of deleting a shortcut in Microsoft's new operating system, Vista.
Now, I have never done this myself, so I have no idea whether or not this is in fact the way it works. However, if this process shown is in fact valid, this is a great example of how security can go wrong.
Taking seven steps to delete a shortcut in Microsoft Vista is absolutely ludicrous. It is understood that this is in place to curb spyware from deleting things that the user does not want to delete, but what would the average user do here? Does Microsoft really believe that the average person knows what the SYSTEM owner is supposed to represent? Do they think that people will have the patience to sit through this whole process? It is similar to the restrictive IP list on the Internet Explorer version of Microsoft Windows 2003. Users have to physicaly add in every web site that they want to go to. Like the shortcut issue above, it is not necessarily a bad idea, but it is a bad implemetation of one.
Microsoft is claiming that Vista will be the most secure operating system ever. If it takes multiple steps to perform the most mundane of tasks, then when no one is using it, it definitely will be. Microsoft runs the risk of alienating their bread and butter customers, the ones who are using it for it's simplicity. Why should I give a reason to shut the operating system down?
There is no such thing as being too secure, but there is such a thing as making the system so secure that no one will be able to use it.