Non Sequitur Scene/Real Life


 * These happen all the time in real life due to its general lack of a coherent plot. Someone should fire the writer.
 * According to the Chaos Theory, life itself!
 * As mentioned in the trope description, Flash Mobs.
 * The Max Headroom Incident
 * Dreams. And 99% of the time, not only do you not mention them ever again, but you forget that they even happen!