I got fired from a job where I had had the most billable hours the preceding two, and the most overtime hours (salaried, but accounted for in client billing). The reason given? "I didn't seem to like working there."

BTW: The principle, at the same time as she was laying off designers, went on vacation to the Galapagos Islands with hubby and then subjected us all to a slide show.

So, no, I'm not going above and beyond unless I am benefiting from it in terms of learning a skill I might use somewhere else. I'm in an at-will state, meaning I can be fired for any reason or no reason.