Summary
You know what we don’t see a lot of inMass Effect? Unemployment. With a seemingly infinite number of jobs available in ruthless mercenary groups and paramilitaries, there are endless employment opportunities for those who know their way around an M8-Avenger assault rifle.
For those who prefer a more pacifist way of life, there are a multitude of bureaucratic roles available galaxy-wide. It takes a lot to keep Council Space running smoothly, especially with Commander Shepard engaging in explosive firefights in residential areas on a near-constant basis. The bureaucrats are the unsung heroes of the Milky Way.

The Galaxy’s Biggest Underperformers
However, who just isn’t very good at their job? Mass Effect fans took toRedditto discuss the galaxy’s biggest underperformers. The original poster pointed to a bartender at Mass Effect 3’s Purgatory as an example of a bad worker, as she never takes drink orders and just dances at a non-stop rhythm for the entirety of her never-ending shift. She shouldn’t be a bartender with stamina like that; is there a Citadel Olympics she can compete in?
Another common choice is Kai Leng, likely the most hated character in Mass Effect. He may have killed Thane Krios, but the majority of his operations proved unsuccessful and in the process, he leaked two secret Cerberus facilities to Shepard. Ultimately, Leng was more of a liability than an asset to Cerberus.

Speaking of the human exceptionalist paramilitary organisation Cerberus, the Illusive Man hasn’t done a particularly good job either, has he? His most successful operation was reviving Commander Shepard, the person who would ultimately be his downfall. Other than that, the majority of Cerberus-related casualties result from their wild experiments going rogue and killing the researchers. I’m not sure how much human advancement The Illusive Man managed, but he was certainly a pain in the backside throughout.
An interesting comment points to Liara T’Soni during her time as the Shadow Broker. The Yahg who was previously the Shadow Broker seemed to be abreast of everything happening in the galaxy, but Liara was unable to predict Donnel Udina’s alliance with Cerberus and subsequent betrayal of the Council. If the Council had its suspicions about Udina’s treachery, why was Liara completely uninformed?
There is plenty of people in Mass Effect that don’t do a particularly good job. If everyone was good at their jobs, then Commander Shepard and his gang of competent world-beaters wouldn’t have too much to do.