How we cite our quotes:
"You may think it charming. I think it's devilish. Do you know he spent the whole of yesterday evening trying to turn me against you, and almost succeeded?"
"Did he? How silly. Aloysius wouldn't approve of that at all, would you, you pompous old bear?" (1.2.78-9)
This is a brilliantly constructed conclusion to the conversation with Anthony. Just as we are inclined to believe Sebastian and write off Anthony’s warning, Sebastian does exactly as Anthony predicted.
"Oh, Mummy likes everything to be a present. She's so sweet," he said, adding one more line to the picture I was forming of her.
Now Sebastian had disappeared into that other life of hi where I was not asked to follow, and I was left, instead, forlorn and regretful. (1.3.4-5)
Charles is left alone because, not having much of a family himself, he can’t understand what Sebastian is dealing with in regards to Lady Marchmain. The same thing happens with religion – the barrier of misunderstanding separates these two friends.
I saw, in my mind's eye, the pale face of Anthony Blanche, peering through the straggling leaves as it had peered through the candle flames at Thame, and heard, above the murmur of traffic, his clear tones […] "You mustn't blame Sebastian if at times he seems a little insipid. […] When I hear him talk I am reminded of that in some ways nauseating picture of 'Bubbles.' […] Boredom […] like a cancer in the breast [...]"
For days after that I thought I hated Sebastian. (1.3.94-5)
Charles recognizes that Anthony is right – Sebastian is in many ways insipid – but he loves him for it anyway. He has no illusions about his friend, but rather accepts him as he is.