I used to meet him sometimes at literary events in London. The first time, I didn't quite catch his name, and found myself standing opposite a grumpy old man clutching a glass of wine, wondering what to say. (Clarification: he was grumpy and old. I wondered what to say. We were both clutching glasses of wine.)
When the penny dropped and I realized who he was, I started gushing about what a wonderful book Riddley Walker is. Disconcertingly, he looked even more grumpy. I realised later that my mistake was to praise a book he wrote 20 years earlier, rather than his latest book. Writers are a touchy lot.