I get a lot of crap email that I don't want. You know how it is, you sign up for something, register a new product, or need to put an email address up to get access to something. And you give them an email address. I know why they do it, they want an email address so they can send you sales material to persuade you to buy more stuff. I'm good with that. I'll even read the first few emails to see what you've got. But usually there comes a time when I don't want it anymore and I want to turn off the emails. They call it "unsubscribe" but that's the wrong term for it, because usually I did not voluntarily subscribe to these emails.
Luckily, most of these emails contain a link at the end that lets you get the email stopped. Mostly these work. The good ones have codes in the link and they go straight to the heart of the matter and without any more interaction from me, I am unsubscribed. That's good. The next best ones want me to type my email address in again before they will unsubscribe me. That's not so cool, but I'll do it.
Then there's a third class of unsubscribing where they want me to enter my name, first and last, and my email address, twice, and then select which newsletter I no longer want. If I'm in a good mood, I'll go through this procedure. If I'm not, I'm going to ignore this unsubscribe process and I'm going to block them at my mailserver and bounce anti-spam messages back to them, and report them for spam abuse on the RBL sites and any other horrible stuff I can do.
I know why they want to make it difficult to unsubscribe. They want to continue sending the stuff to me. But have they ever considered that this is not a very good thing to do? It enrages me, it makes me swear to never buy anything from them again, and it encourages me to go out of my way to make things difficult for them. I will put far more effort into being a bastard about it than the effort I would have expended in filling out their stupid form and submitting it.
I believe that most people in charge of marketing departments, especially mailing marketing departments, are really really stupid.