Rule of thumb for the day:
If you are in a situation where the problem seems simple, the answer clear, and everyone else around you is acting like an idiot; if you are in a situation where it seems obvious that you are the smartest person in the room; in that situation, as soon as you recognize you are thinking this -- STOP.
Step back, turn off the machine, take a long careful look around. Because the odds are against you.
Writers over the ages have pointed out that only two kinds of people are completely confident; those who are experts in their field, and those who are vastly ignorant of what is involved.
There's even a name for it, now; the Dunning-Kruger effect (which, according to the original paper, is that confidence maps inversely to skill.)
One of the hardest things to know is when you don't know that you don't know. As Feynman put it in his famous address, "You are the easiest one to fool." We fool ourselves all the time. We want to believe in our skill and the implied status it gives.
So use this. Use that same psychological crutch as a litmus test instead.
If you think everyone else in the room is an idiot.......then, in reality, it's probably you.