The secret British mission to find and destroy the Veinticinco de Mayo, Argentina's only aircraft carrier, that threatened the Royal Navy's Task Force sent to recapture the Falkland Islands.
The worst part is that the Argentinians could have won if they planned it properly. Their Air Force focused on taking out the RAF aircraft instead of the ships. Had they done the contrary, they would have won.
Never the less, the population of the Falklands does desire to be part of the UK, so I suppose, the Argentinian tactical deficiency was a good thing.