I once saw a bumper sticker that read, "The more people I meet, the more I like my dog." With all the stupid stuff that happens in life, I've come to realize why someone might think this. Dogs make better friends than some people because, if you treat them right, dogs will love you unconditionally, are always happy to be with you, and they won't turn around and stab you in the back when you least expect it.
As long as you treat your dog right, it will always love you, no matter what you do. You can stay out late, and your dog won't get mad at you. You can yell at your dog, and ten minutes later, it will still want you to pet him or play with you. You can tell your dog anything, and it will not judge you, or hate you because of what you said. When you are sad, your dog will know, and try to cheer you up. I hurt my knee when I was younger, and had to be on the couch or a week. My dog sat by that couch with me the entire week, just to make sure I was ok. These are some of the things that show he loves you.
Dogs are always happy to be around you. When I came home, my dog used to run up to me, and jump all over me, wagging his tail in the typical happy dog way. Your dog won't care where you have been, he will just be happy that you are finally home, and can play. I love the fact that a puppy's favorite place to sleep is in your lap, or by your feet. My dog liked to follow me around the house, just so that he was near me. He"d always be sad when I had to leave, but always loved it when I came back. It doesn't matter what you do when you"re away, your dog is just happy that you"re there.
The best thing about dogs, I think, is that they will never stab you in the back when you least expect it. A dog won't borrow money from you, and never pay it back. A dog won't steal from you, or lie about you, or to you. A dog won't even call you up one day and say, "I"m really sorry, but your ex and I are together now", which has been known to happen by some of my so-called, "friends".