I've always been able to multi-task pretty well. If one feature/bug requires a long test run, or review by someone else, or an email back and forth I can often switch over to another copy of the code and work on another. This has actually backfired with micromanaging bosses, though. I remember once the whole engineering team at a startup agreed I could fix the file size of an app as I went. So I worked a new file compression into a commit that involved the files anyway. Unfortunately, it looked like it took three days when it actually took a couple 10 minute sessions with a glob command line as it went through the review process, but was interspersed with other work.

Well the manager went nuts against this change. Argued in emails citing problems that had long been fixed in the review thread emails, making up a bunch of incorrect complaints (he couldn't understand the difference between AAC and AAC+ and how they had different device support, and after having it explained to him, started with just vague "it's too much change" bullshit that couldn't be corrected). When I talked to him over IM about it later he admitted the real reason was because he said it took me days to do it and he wasn't going to approve any work on it no matter what. He was always the sort of guy who did the popular thing in big meetings with the employees, then pulled the rug out in private.