Jeremy Paxman doesn't hold back when contestants on University Challenge respond with the wrong answer.
But what happens when the quizmaster himself blunders?
The show's bosses have admitted the 'correct' answer given on Monday night's show was, in fact, incorrect.
The BBC has apologised for the mistake, although it said it did not affect the outcome.
In a bonus round - after Cambridge's Clare College won the starter questions - the students were asked to identify the composers of various requiems.
Although the required answer after one clip, according to Paxman, was Dvorak, viewers identified it as a Gregorian plainchant.
The BBC said: "The excerpt we played was not composed by Dvorak himself. We apologise to both teams and viewers and are grateful to those who pointed this out."
Some viewers were also concerned about another answer after the teams were asked to name a character from Jane Austen's Pride And Prejudice. Clare's answer of "Eliza" was judged to be wrong, while "Elizabeth" was accepted, but one viewer claimed she was referred to as Eliza no fewer than 22 times in the 200-year-old novel.
Clare beat opponents Christ Church, Oxford, on a tie-break question.