If there is a vey obvious link that immediately unsubscribes me then I will use it. By immediately I mean "when I click this link I am removed from all future mailings without having to do anything else and without a delay".

If it asks me to confirm my email address or asks any other action or uses deliberately confusing double negatives ("confirm which email lists you don't want to stop receiving") or asks me anything else before confirming my opt out then I will immediately return to gmail and click "report spam".

I run a fully opted in newsletter and very occasionally see "reported as spam" in my dashboard which I assume means this action still has some very minor negative action for the sender if they are using a third party provider (mailchimp etc) to manage their campaigns.

"unsubscribe" should mean unsubscribe not "present me a number of options to try and confuse people into staying".

I notice that with some campaigns when you hit "report spam" in gmail it asks if you would like to unsubscribe. I'm happy to do that if it's presented as an option - though I haven't seen it for a while.