Happiness is the last of...

the icecream left in the fridge. The final lick of jam in the pot. The supreme joy you have when you get up thinking you are late, and realise that you have an hour more to sleep. The last hour that comes as a bonus, and you extract the maximum juice out of it.
Sure, when you are reaching the end of it, like the Harry Potter series, or any other good book or movie, or when the alarm rings, there's a tinge of remorse, but all in all you are still happy for the last taste of heaven.