I bought a vintage table saw last summer and almost immediately broke the vintage drive belts. Wonder of wonders, somebody had done the same thing and posted pictures of his repair online. However, my saw’s setup looked different than the photos. I spent a good 8 hours patiently jockeying the loose parts into alignment without success. Then it dawned on me: it just can’t be this hard. I took a fresh look at my saw and realized one of the bearings had popped out of its housing. I cleaned the parts, popped it back in and was done in 20 minutes.
Another story with the same outcome: many years ago I was driving a VW bus on a very bad road in southern Mexico when a shock absorber came loose behind one of the wheels. I spent a couple hours trying to get it back on as a steadily growing audience of local indigenous men watched me. Finally one got impatient and pointed something out with sign language. The bolts that went into the top and the bottom mounts were different. And you could easily tell what was the bottom bolt because it had more road grit on it.
The lesson is, there’s usually a logical way to do things and people who are not bogged down by intellectual musings will find that way automatically by following the path of least resistance. Good designers of mechanical things know that and design accordingly (a notable exception being 1970s and 80s Detroit cars, where they’d often create special tools to make up for the fact their engine compartments were inaccessible) and ad writers should do the same.
If a reader has made the commitment to proceed through your letter or other body copy, they are fully intending to follow that path of least resistance. They know that A is followed by B, or supposed to be. Put a surprise in the road when they’re about to get to B—a special offer, or a new benefit—and it will get maximum attention. Change course without adding a benefit, and you’ll confuse and irritate and lose the reader. Keep this in mind when you’re framing out your next project.