For the sake of illustration, let's create a new unit of measurement:
Active Focus Unit—An Active Focus Unit (AFU) is defined to be the amount of focus that it takes a user to perform a simple, common task. For example, finding, pointing to, and clicking an arbitrary site's logo to navigate to the homepage = ~1 AFU.
Navigating to the root of a site is a very common function, and the vast majority of successful sites provide this function in the same general area: the top of the site, normally at the left.
Let's also define our goal to be the following:
Minimize the user's cumulative AFU output for any given task.
Now for an example:
Alice is navigating Clothing Inc.'s site for the first time. The homepage shows categories of products. She notices immediately three large headers: "Men", "Women", and "Children". She clicks on "Women". = .8 AFUs
She now sees that she's viewing only "Women's Clothing", as the page header tells her. She sees several categories highlighting a few popular products in each: "Jeans", "Dresses", "Tops"... She clicks "Dresses". = 1.1 AFUs
She finds a dress that she likes, and selects her size, then adds it to her cart. = 1.2 AFUs
She has spent 3.1 AFUs performing basic navigation through a series of common steps. Not too bad.
She still has more shopping to do, so she visits another clothing site.
We Sell Stuff
Alice visits We Sell Stuff's site next. Their homepage shows 100 products per page. She tries to figure out if there's any organization to the madness to make this more manageable and to find what she's looking for. = 2.4 AFUs
Alice finds a "Search" button and clicks it. It takes her to a new page where she can type her search request. She types "Purses" and clicks "Search". = 1.3 AFUs
Alice sees another button called "Sort". It again takes her to another page to let her pick what property to sort by. She sees "Price", but can't figure out if that's low-to-high or high-to-low. She clicks it anyways. = 2.1 AFUs.
Alice finds out that this was not low-to-high like she wanted. She goes back to sort by "Rating" instead. = 1.7 AFUs
At this point on We Sell Stuff's site, Alice has already spent 7.5 AFUs and hasn't even found a the products she wants to look at yet.
Sure, this is a hugely contrived example, but the points remain: Don't focus on minimizing clicks; focus on providing an intuitive experience that removes as much friction from the user's experience as possible.