“No,” said Miss Marple. “Murder isn’t a game. - Agatha Christie

One forgets how human murderers are.

I suppose next time I come home I shall find you wearing false moustaches — or are you doing so now?'
Poirot winced. His moustaches had always been his sensitive point. He was inordinately proud of them. My words touched him on the raw.
'No, no, indeed, mon ami. That day, I pray the good God, is still far off. The false moustaches! Quelle Horreur!’
He tugged at them vigorously to assure me of their genuine character.
'Well, they are very luxuriant still,' I said.
'N’est-ce pas? Never, in the whole of London, have I seen a pair of moustaches to equal mine.'
A good job too, I thought privately.

It's as easy to utter lies as truth.