Instead of worrying or concentrating on everything wrong in the world, a person is focused on just one item and that is having fun. a good example is a visit to a casino. everything there is upbeat and time really does fly, especially if you are winning.
pinched from a similar thread
“When you sit with a nice girl for two hours, you think it’s only a minute. But when you sit on a hot stove for a minute, you think it’s two hours. That’s relativity.” – Albert Einstein