When you commit a typographical error, but the error itself just happens to be another correctly-spelled word that _might_ actually work in
the current context, which makes it far more
confusing and hard to spot than if it were just a
misspelled word.
Kevin: Hey look, my murder is on the TV!
Everyone Else (after a period of
confusion): ..... did you maybe mean "mother"? .....
Kevin: whoops sorry
Everyone Else: Looks like Kevin is Kevining again...