Competent evil help is hard to find. How else can you explain how the Evil Overlord's General is a complete nincompoop, mooks are all dimwits who graduated from the Imperial Stormtrooper Marksmanship Academy, the elite special forces consist of a Quirky Mini Boss Squad, and all the ninjas are standing around in plain sight or queuing up to attack the heroes one at a time?
Sometimes, it seems like the lead antagonist has deliberately chosen the most incompetent, craven, cowardly, or just plain unreliable underlings around... the trope often culminates in a second-in-command that, instead of being the best of what the lower ranks has to offer, seems to be the living distillation of everything that makes the incompetent underlings what they are. This version is often punctuated by having the right-hand man actually secretly trying to undermine and/or replace the Evil Overlord, but just too incompetent to be a real threat.
Of course, the simplest answer for why the evil master is surrounded by idiots is because you'd have to be stupid to work for him. The underlings' being Too Dumb to Live may well explain why they continue to work for an abusive employer, but we still have to wonder why the Evil Overlord hired them in the first place. We can't pretend he's not aware of his hirelings' shortcomings since he never hesitates to exclaim about them: "FOOLS! CRETINS! BUNGLERS!" (there always seems to be a basic formula of Mild Insult! Not-So-Mild Insult! EXTREME INSULT!, if it's not a case of Arson, Murder, and Jaywalking), sometimes, "It's so hard to find good help these days..." and of course, the oft-repeated Trope Naming line, "I'm surrounded by idiots!" - sometimes accompanied by a facepalm. After one too many failures, the boss tends to say "If you want something done right, you gotta do it yourself!" and then proceeds to do far better at any given mission than his underlings have ever done, making you wonder why he didn't just do this in the first place.
Occasionally, one of them will respond to this exclamation by looking around and asking, "Where?"
This trope even made the Evil Overlord List.
Of course, one possible explanation may be that smart minions tend to try to take over... or perhaps any minion might be trying to take over, but a smart one might actually succeed.
When the boss is an incompetent dolt, you have a General Failure or a Pointy-Haired Boss. If both the boss and his minions are morons, then you are dealing with a group of Harmless Villains (such as The Family for the Whole Family).
See also Conservation of Competence and Beleaguered Boss. Polar opposite of it is Surrounded by Smart People. Contrast Too Dumb to Fool. If the character being surrounded by idiots lashes out on them, then it's Enraged by Idiocy.
Here is a compilation with a lot of examples.
