1. Well that one's obvious. Moving on to number two...
2. Those cold feet of yours now have their own person space heater to accompany them.
3. You always have someone there to talk to (though they'll most likely fall asleep in the middle of your story).
4. You have someone to introduce into your covered wagon.
5. There is the possibility that someone else will get you a drink in the middle of the night.
6. You'll have someone around to tell you the funny things you said last night in your sleep.
7. People tend to be less annoying than alarm clocks in the morning (though often harder to turn off).
8. You have someone there to tell you when you should go to bed, even if it does not sound like the most entertaining of your options.
9. When they snore, or start talking nonsense, you can record it (it really is more fun than I would have ever expected).
10. Cause you love them. And cause everyday begins and ends with you seeing your favorite person in the world.