Jason mentions the following cities where he lived: London, Ontario (Canada), Toronto (Canada), London (UK), San Francisco (USA), Hong Kong (China), Taipeh (Taiwan).
He assumed he liked these cities (except for London, Ontario) because they had big, dense populations (many people living closely together) and a lot of interesting stuff happening.
Jason also loved DOWNTOWN (the city center), but hated THE SUBURBS (other areas away from the center).
WHY?? Watch the first two minutes of the next video. We're looking for ONE WORD.