I’d be the first to admit that I’m no “deisgn guru” and that when you come from a developers back ground trying to work out how users will use a system (be it an e-Commerce web site or a Twitter Client) it is always tough to work out just how the users will go about their business. There is a real hurdle to overcome when trying to use a system as a user rather than as someone who’s deisgned (in terms of workflow at least) and built it.
It’s easy to get into the kind of mindset of “well of course you then click X to get to Y” which is why usability testing is really important. We have to remember that web sites will be used (hopefully) all the time by people who’ve never been there before and hence things should be logical and flow… and when this is not always so simple provide enough guidance to aid the user.
Sometimes folks can go too far… and in fact confuse the user. Take a look at the screenshot below and think about where you’d instinctively click to go to the next page. Bear in mind that it’s likely you’ve just scanned down the text (although I’ve blurred it here but please pretend that the text might be semi-important).

I would think that most people would click the right facing arrow at the centre bottom of the page, bearing in mind that they’ve just scanned the text above. Yup, the one with the word continue written next to it. Either that or they also see the button at the top right and then may think “Oh, which one do I press and does it matter at all?”. Sadly you’ve got at best a 50% chance of going nowhere. In fact these arrows at the bas of the page are not buttons at all but simply ‘helpful’ instructions about the arrows that will appear at the top right corner of each page.
So what’s the lesson here? Testing is important… and it’s no good just testing something yourself as you know what and how a system is meant to work.