Capacity

     After dinner Barry would read his poems. Usually, he said, 'I'm not going to be an egotist tonight. I'm not going to read my poems.' And usually Désirée would cry, 'Oh do, Barry, do.' Always, eventually, he did. 'Marvellous,' Désirée would comment, 'wonderful.' By the third night of her visits, the farcical aspect of it all would lose its fascination for Sibyl, and boredom would fill her near to bursting point, like gas in a balloon.  To relive the strain, she would sigh deeply from time to time. Barry was too engrossed in his own voice to notice this, but Désirée was watching. At first Sibyl worded her comments tactfully. 'I think you should devote more of your time to your verses,' she said. And, since he looked puzzled, added 'You owe it to poetry if you write it.'
     'Nonsense,' said Désirée, 'he often writes a marvelous sonnet before shaving in the morning.'
     'Sibyl may be right,' said Barry. 'I owe poetry all the time I can give.'
     'Are you tired, Sibyl?' said Désirée. 'Why are you sighing like that; are you all right?'
     Later, Sybil gave up the struggle and wearily said, 'Very good' or 'Nice rhythm' after each poem. And even the guilt of condoning Désirée's 'marvelous . . . Wonderful' was less than the guilt of her isolated mind. She did not know then that the price of allowing false opinions was the gradual loss of one's capacity for forming true ones. 

- Muriel Spark, “Bang-Bang You’re Dead”.