Always and inevitably each of us underestimates the number of stupid
individuals in circulation.
The probability that a given person is stupid is independent of any
other characteristic possessed by that person.
A person is stupid if they cause damage to another person or group
of people without experiencing personal gain, or even worse causing
damage to themselves in the process.
Non-stupid people always underestimate the harmful potential of
stupid people; they constantly forget that at any time anywhere, and
in any circumstance, dealing with or associating themselves with
stupid individuals invariably constitutes a costly error.
A stupid person is the most dangerous type of person there is.
Carlo Maria Cipolla's five fundamental laws of stupidity