It was a mistake because of the man who plonked down into the seat next to me. I happened to sit across from two Chinese dudes, and Mr Man, whom we shall henceforth refer to as Racist Assface, assumed that none of us could speak English. He turned to me and said, really loudly, "Do you know if this train goes to LETCH-WORTH?" (Anyone with the slightest degree of sensitivity will be able to picture the manner in which he spoke.)
"Yes," I answered calmly. "It does."
"Oh!" Racist Assface said delightedly. "You speak English!"
"Yes," I said. "It should arrive at Letchworth in 28 minutes' time."
"You speak really good English," Racist Assface replied.
I smiled frostily. And then his head exploded.*
* I may have simply wished this last bit.
I still can't quite believe this actually happened.