Worst unsubscribe page I recently found had a big, colored button that said "update my preferences" that actually... resubscribes you. Because it already quietly unsubscribed you as soon as you clicked the link in the email.
And they also say on the page to allow a few business days for it to take effect so you will assume it's delayed and forget about it.
Technically they did explain it on the page, but it was clearly intended to trick people