Sometimes it feels like all mass transit systems do is apologise for running behind schedule. New York City's Metropolitan Transit Authority decided to create this video explainer for exactly why you were waiting so long for the L this morning. And they did it in with cute 8-bit graphics.
One delayed train can throw the whole system out of sync, creating what engineers call a "service gap" (you, waiting on the platform forevvvvvver). But as large numbers of people accumulate on the platform between trains, those service gaps end up creating even worse delays — people don't board the trains as quickly due to overcrowding. So engineers will actually hold a train in front of the service gap to allow for a better redistribution of passengers. Eventually the gap disappears and you get to work on time. The more you know!