Helpful at first, but the extension interrupts every window or tab spawned by a monitored service as if it is the first one. I sometimes feel I have spent a large portion of my allotted time waiting on the Pause green butterfly. If you are setting up a new account at a business site that uses, say, Twitter for authentication, the tiny window that pops up gives you the green butterfly instead of the form you need.

If I turn Pause off, go to a webpage on the list, and then turn Pause back on, it will "pause" that webpage, even though I opened it before I turned Pause on. On a page like YouTube, this leads to things like losing my queue, meaning I have to construct it all over again. Pause shouldn't behave this way.