There are some annoyances that would require more than just a casual google or from the top of the head answer. Some questions and problems require effort in answering, and the bounty system helps getting these questions answered.
However, for annoyances that are really hard to solve, I would be ready to put a bounty of hundreds if not thousands of points. If only the bounty could stand for more than a week; a week is short time to get a complex problem of a user solved remotely.
Would it be possible / would it make sense to prolong the time for which a bounty of 500 or more stands?