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People think it’s all about misery and desperation and death and all that shit which is not to be ignored, but what they forget is the pleasure of it. Otherwise we wouldn’t do it. After all, we’re not fucking stupid.
— Renton • Trainspotting

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker argues that outsiders see only the misery, desperation and death, which are real and not to be ignored, but overlook the pleasure. That enjoyment, the speaker insists, is why people do it at all, since they are not stupid.
Context reviewed