Over in America, transportation engineering academic Lewis Lehe was so confused by this oh-so-common commuting phenomenon that he did the maths to figure out how it happens. Then - naturally - he made a game to help us understand it. You can play it here. Lehe explains how it all works: 'If the bus gets a little behind schedule, then there will be a greater-than-average number of passengers at the next stop, because passengers arrive at stops at a steady rate. The extra passengers consume extra time boarding and alighting, which makes the bus get even further behind.' So even a tiny delay can be disastrous, and send buses queuing around the block. You know what this means, don't you? It's your fault. Yes, you, with all your bloody fumbling for your Oyster card and asking the driver if he's going to St Paul's. Quit ruining London, people!