The normal ATM is similar enough to all other ATMs that you never really have to read anything completely. I'm sure many of us have had to operate an unfamiliar ATM in a less-than-sober state, and had no major problems doing it (I know I have). The reason is that our brain has developed a bunch of pattern-recognition tricks to dealing with ATMs because we do it so often.
There are a number of well-established ATM screens that everyone is more or less familiar with: Pick a Language; Enter Pin; Select Transaction; Select Account; Select Withdrawal Amount; Enter Your Own Withdrawal Amount; Agree To Fee; Another Transaction?; Would You Like A Receipt? Most machines don't have all of these, but generally, these are present in some combination in any ATM you come across, and, they usually come up in this order.
Most people skim the screen looking for some key elements so they know what screen they are dealing with. The subconscious thought process goes something like this: "I see the letters 'PIN', and there is a box for text entry - it means I need to enter my PIN" or "I see a bunch of numbers for menu items - so I need to press the one that says '100', or has the word 'other' in it". Or "I've just picked how much money I want, and now I see a highlighted $2.00 - that means this is how much they want to charge me. I should find a button that says 'Yes'".
And this is where the WaMu interface fails horribly - by substituting "standard" words for "friendlier" synonyms, it robs us of the ability to use our long developed pattern-recognition to figure out what the machine wants from you. "Secret Code" may mean the same thing as a "PIN", but it doesn't look the same to the eye, and as a result, you have to read all of the text on the screen. Likewise, "Sure" may mean the same as "Yes" (but with more pep!) but takes a couple of extra seconds to find.
Anyone who's ever used their ATMs should know what I mean - it takes two to three times longer to get a basic withdrawal done than even at the dinky grocery machines which still connect to the network via modem. What's sad, is that there must be people who are paid money for "user interface design" who were responsible for this atrocity.
PS: Funny post on the same topic