Another post, in my recent non-substantive, but fun for me, series of posts (March 18: singletasker):
Opposite of multitasker, a singletasker is one who only takes upon one task at a time, and follows it through to completion. Often used sardonically when someone is bragging about their supreme multitasking skills.
Tim: "Today I'm only going to focus on finishing my grant report
and not answer the phone, email, blog, work on that referee report, prepare for class, and write that abstract for the conference presentation simultaneously."
John: "You are such the singletasker!"
Tim: "I can't even respond to you at this time, because then I'd be multitasking."