“Make it easy to unsubscribe. Unless you want to end up on a black list faster than you can say ‘spam’ and generally annoy people to the point they’ll never buy from you again.”
Nothing will leave a bitter taste in your reader’s mouth more than not being able to easily unsubscribe. Make the best of a bad situation and let your unsubscribes go without a hassle. Add the unsubscribe button at the bottom of every email.