Two words
It only takes two words. Two simple words. But, they are the hardest words to ever utter. We all know the words, but saying them is impossible. They are "the words that must not be spoken." It's even harder to say them and mean them. Damn near impossible. Of course, if you say them and don't mean them then...well, the whole thing is pointless. If the third word is "but" then it doesn't matter.