Too Much Security?

This blog from The New York Times raises a good question: Isn't there a point where security is too much and affects productivity?
It reminded me of the discussion we had in class about the possibility of having a 100% safe flight that would cost a fortune. Like in that example, I think we ought to find balance when it comes to online security.
I mean, just think about all the logins that we do every day, it became such a routine to answer security questions, recognize texts, find that perfect 12 character long password that contains at least a number, a capital letter and doesn't represent a word from the dictionary, and that needs to be changed every 30 days...or when you have to relogin because your session expired or you left your computer for 5 minutes.
The more complex the passwords we choose get, the more complicated it is to remember them and the greatest the temptation it is to write them on a piece of paper next to our computer, which in the end defeats the whole purpose of the password.
At the end of the day, all the time spent creating, using, retrieving forgotten user ids or passwords amounts to time that is not used for other purposes and it negatively affects our productivity in the workplace.
Security is important, but just how much of it is enough?