Pain in the ass
In science, a pain in the ass is a type of highly annoying inconvenience, or object of extreme nuisance.
Categories
Things that are a pain in the ass are divided into two main categories:
Activities
When performing a task, an individual may be required to endure disproportionate amounts of effort relative to what's considered normal or ideal. In these circumstances, the task itself is considered a pain in the ass. Reorganizing filing cabinet after a toddler gains access to it is an example of one such circumstance. So is planning a wedding, interviewing for a job, removing poop from underneath a shoe, or shampooing a cat.
People
The kinds of people who personify this classification are stubborn, dense, demanding, uncooperative, pissy, whiney, or any number of these traits combined.