According to the text, Parvez endures the worst experience of his life during a shared meal with his son, Ali, at a restaurant.
The main reason Parvez characterizes his experience so poorly is because Ali's insolent and judgmental attitude made him feel disrespected as an elder and ineffectual as a father. During the meal, Ali questions his father's indulgence in alcohol. Meanwhile, Parvez tries to quell his rising anger but is unsuccessful.
Parvez knew he was getting drunk, but he couldn't stop himself. Ali had a horrible look on his face, full of disgust and censure. It was as if he hated his father.
He had explained patiently to Ali that for years he had worked more than ten hours a day, that he had few enjoyments or hobbies and never went on holiday. Surely it wasn't a crime to have a drink when he wanted one?
As the conversation continues, Ali condemns Parvez's other lifestyle choices. He accuses his father of enjoying pork pies and crispy bacon sandwiches and of not being a good Muslim. Frustrated at losing control of the conversation, Parvez drinks more alcohol. Meanwhile, Ali lectures his father about the excesses of the West and proclaims that he is too entrenched in the western lifestyle. Parvez is grieved that his relationship with his son has seemingly deteriorated beyond his ability to heal; he feels helpless and angry.
Parvez called for the bill and ushered his boy out of the restaurant as soon as he was able. He couldn't take any more. Ali sounded as if he'd swallowed someone else's voice.
As they leave, Parvez thinks that this is the worst experience of his life: at this point in life, he has been rendered both impotent and inconsequential by influential forces in his son's life that are beyond his control.
'What has made you like this?' Parvez asked him, afraid that somehow he was to blame for all this. 'Is there a particular event which has influenced you? 'Living in this country.'
'But I love England,' Parvez said, watching his boy in the mirror. 'They let you do almost anything here.' 'That is the problem,' he replied.