Balance my checkbook. I hate not knowing how much money I do or don't have, but there's always something else more "urgent" that needs doing first.
Probably the thing that does it for me is software problems --- in particular, cleaning malware off a computer. It's never a simple process, it's never a short process, and you're never really sure if you've gotten it all.
The first time I was asked to serve as a Table Leader for the AP Computer Science Reading. I don't know what it was about that experience ... but for my first time as a leader, I was assigned to the hardest possible question. And because it was so hard, nobody really took the time to explain how the job worked; there wasn't any time. We were behind even before we started. I more-or-less had to say "okay, I think this is what my leader did for me, so I guess that's what I'm supposed to do", and tried to make the job work. They keep asking me back into the leadership, so I must've done okay ... but, it was harrowing.
In retrospect, I tell myself that being thrown into "the deep end" was a sign of respect --- they wouldn't have done it to me if they didn't think that I could handle it.
Oh, dear, now you're getting into the course on ethics that I'm teaching. In my opinion: no, the ends never justify the means. Often the "means" to the end are people, who ought to be considered as an "end" in and of themselves.
I'm a big fan of asparagus and cherry tomatoes. Coconut (especially dried flakes of coconut) is inherently evil.
Cleaning the desk. (See previous item about "haven't balanced the checkbook in months".)
My dear family is about to head off for ten days of family vacation with the extended family --- without me, because I have to stay behind and teach. I'm trying to plan for things to do that will be fun for me on my own, and I hope I'll manage to get some of the housework done that just never gets anywhere ... but I'm really sad that I'm not going.