I really wish you would have made it less annoying to opt out of emails
 

I had to reset my password then come here and navigate the user preferences... there should be a link that says "unsubscribe" like everyone else has.

You can turn it off globaly right here: Edit Options (Default Thread Subscription Mode)

Individually (but all listed): Subscribed Threads

In addition to druuna's post, you can also unsubscribe a thread when you have it opened in the browser using the thread tools at the top of the thread.