I got a great article from my son's school titled the same. I felt how true the statement was. Dogs have and give you that unconditional love. Yes there is a small expectation you provide food and water, but he is always happy and doesnt hide that excitement anytime he sees you.
I probably have read or heard something similar, but unless you own one and vitness it for youseself you dont really appreciate it.
The world would be a happy place if only you could have the same relationship you have with your dog, with other humans around you. (i mean me included...) it totally changes your perspective for love and affection.
The fringe benefits, keeps you trim (as you have to take him to walks), gives you good diversion from everyday stress when you play with them. My wife has reduced blood pressure in just the last 3 months after we got him. (sure the kids do their part to make sure it doesnt stay low :-)).
Iam sure the puppy habits of chewing the coffee table, some minor mistakes when he grows up can be easily forgotten, and woudnt seem anything you would even notice for all the great puppy love he showers on you.
btw: Our puppy is Troy, He is a labradoodle, we got him when he was exactly 8 weeks old a day before christmas in Dec 2007. Surprisingly his birthday is just a day after our anniversary.