That would depend on the job and level.
For me, I'm a coder and at the associate level. For me the least liked thing would have to be the not being able to choose what you work on and the business constantly changing their minds. So at work the business will say "Do this, this and this" but when I do that they turn around and go "this isn't what we wanted so change this this and this". I can give them everything they ask for and they'll accept it then turn around and want it gone or completely changed.... 2, 3, 4, 5 times in a row. And I have no say or control to be like "Are you sure about this? Is this what the users will want? Have you run surveys?". I just have to be a code monkey and code.
But say I was QA. The least liked thing would be the having to document and write up every single step taken for every single test run. They have to write up excel sheets with everything they will test, and before ever getting the completed code. And the business loves changing requirements in the middle of development, so their test cases change often, without notice, as no one gives them a head up. They are not free test without limitations and are bound to their test steps. So that would suck and is why I'm not a QA person.
But if I was a manager then I'd say the meetings. Managers are constantly in meetings and they last for hours. So if I was a manager that would be the least liked thing.
So it really just depends on your job and level.