E-ficiency
The ability of a website or browser to not make you want to scream. If you can get to where you need to be without being confused, it's E-ficient. If you're lost in a sea of buttons, it's not.
I clicked on a button and it took me to a different website. What is this?!
I tried to log out and it took me to my childhood. This is not E-ficient.
There are more buttons on this site than my ex's text messages.