-rampant bad/incompetent management throughout the organization. I know numerous colleagues from all pay grade levels and work areas, and the vast majority of them have issues with their manager. Common issues are micromanagement and poor project management skills, with everything getting frantically done at the last minute instead of adequately planned out in advance
-the direct manager has too much power over you, your work and your life. They can turn down vacation requests, they can dump unreasonable amount of work on you, they can preclude you from pursuing professional opportunities like going on a temporary appointment with another agency or UN entity, and they can bully you as much as they want. The various mechanisms that are supposed to deal with this--like the ombudsman's office or the ethics office--are useless. Thus, you might end up having a great career with colleagues that are like your second family and enjoying the full 30 days of vacation you are entitled to every year, or you might end up being overworked, miserable, and not being able to take any vacation for years. There is no way to tell in advance what your experience will be like. The UN interview process--only virtual, even before COVID--gives you no glimpse into the culture of the particular team you might be working with. It's a huge gamble.
-if you are an American, you have to pay taxes on your UN income while your colleagues from every other country do not. The worst part is not even the financial pain (the UN reimburses most of them), it's the hassle of dealing with two utterly unhelpful bureaucracies (the UN tax office and the IRS). Instead of having your taxes deducted from your salary and getting a W2 like in a normal job, at the UN you have to calculate your quarterly estimated tax payments and pay them yourself, and then at the end of the tax year you get a statement of taxable earnings and have to either do your taxes by hand (good luck trying to get a tax software accurately deal with your UN employment situation) or spend big bucks on an accountant. In addition, the UN has its own internal taxation system (the staff assessment) which are NOT tax deductible. Thus, if you are an American you end up earning 10% less than your international colleagues, even after getting the partial tax reimbursement from the UN
-the salary system is idiosyncratic. First, your salary is dependent entirely on your pay grade and salary step, regardless of the actual job, so an admin assistant and an economist at the same pay grade end up earning the same amount. It is also structured such that you get an insignificant raise with every promotion, because your raise is tied to your current pay grade/step and because the insurance premium increases with increasing salary. Finally, people with children get all kinds of financial perks like educational grant for their children (up to age 25 I believe!) and dependency allowance, with single/childless employees not getting anything equivalent. Your colleague could be earning double your salary just because he has 5 children, for example. Basically, the salary is lucrative for non-Americans who don't have skills that are valued in the private sector and who wish to have many children. If you don't fall into this category, you won't be too thrilled with your compensation package.
-the bureaucracy is as maddening and as bad as they say. I spent most of my first year at the UN actively trying to resolve various bureaucratic problems. While many companies told their employees at the beginning of the pandemic that they can work from home until at least 2021, the UN kept extending our WFH arrangement a few months at a time and you needed to get your manager's permission and jump through bureaucratic hoops to leave NY. The pandemic also highlighted the second-class status of single people at the UN, as they had a harder time getting approval to leave NY and they were also pressured to return to the office more than their married colleagues
-most of the male employees are married with stay-at-home wives and lots of children and are somewhat chauvinistic, while a lot of the female employees are single and feminist. This creates a rather INTERESTING cultural dynamic at work, to say the least...
