Late last night, while I was negotiating the London underground filled with eastern Europeans and African shift workers, a +221 call buzzed on my phone.

"Hello?" I said.
"'Allo. C'est qui?" asked the caller, a classic Senegalese way of making a phone call.
"Who are you?" I asked back.
"I'm looking for Rose. Rose Mbaye. She's a Senegalese. Are you a Senegalese?"

His squeaky voice made me think it was a friend playing a trick on me. While people rushed around me, I stood in the ticket office and giggled at this ridiculous conversation, enjoying it for its unique west African flavour. The guy eventually hung up. A complete, random mystery that in the cold light of a London Sunday night, was ultimately cheering.