London Gatwick airport's page says a simple "your request has been processed", what does this mean? how are my expectations being managed? (they aren't). Which newsletter was this again? Oops, how do I sign back up I didn't mean to click on that! This page looks particularly lazy, possibly not even a web page with any formatting. What makes this worse is that it is from a third party mail list management service ... it doesn't look like the whole user journey is considered equally.
Kobo's page was quite plain although with their branding and managing expectations - I know that I am now unsubscribed from marketing and also that I may still get some transactional emails.
A slightly older subscription I had was to be in the audience for BBC shows, they promptly process the unsubscribe within their site and give you a little teaser to hook you back in by showing you what you are missing.
The Brighton Fringe festival and Proud Ballrooms both use the same system, with the same formatting. Plus points for the optional setting of how many more emails to get before the stop emailing you. I'd say a big negative is the white label feel, coming from a branded email the experience is hardly seamless.
Ticketmaster's unsubscribe link takes you to a completely branded page as though you were on their site searching for tickets. Again it sets the expectation of when you'll be taken off the list and apologises in case you are already scheduled for a mail shot.
Unique so far in my email list clean up was the local karting track. They take you to their site and default the email options to no, but giving you the chance to add an option in. The interesting bit was the opportunity to supply social media details to be contacted by instead.
The poor sites give vague messages on sites that are little better than placeholders. And you still get emails. And then another one.