Love is the Chief Cause of Insomnia

Think about it.

At first, you can't sleep because you are always thinking about that special person.
Then you can't sleep because you stay up all night shagging.
After a while, you can't sleep because you've had kids and you love them and take care of them when they call out for you at all hours.
Then, they grow up, have lives, and you still can't sleep because now you stay up worrying about them.
Finally, you more or less stop worrying about them, but you still can't sleep because you love yourself and worry about your mortality.

Eventually, you die and catch up on some rest.