What could be cuter than puppy pictures? But despite their awww factor, puppies are a big commitment. Turning these jumping, chewing, nipping, yipping, piddling, pooping little creatures into well-behaved dogs takes a good deal of time and effort.

Without that time and effort, the puppies in these pictures -- no matter what the breed or bloodline, no matter how adorable -- will easily develop problems such as nervousness, aggression, and house-soiling.

Experts consider puppyhood, particularly the first three to four months, the most important period of a dog's life. In that short window, a dog's experiences shape his opinions about what's safe and what's scary -- opinions that can be hard to change later on. During that time, puppies need exposure to all kinds of people, sounds, places, and situations--a process known as socialization.

Puppies and young kids look great together in pictures, but are rarely a good match. As well as socializing, puppies need intensive housetraining, obedience training, and supervision around kids to make sure no one gets hurt. Not to mention that they wake you up at night! Unless you have lots of time and energy, a calm adult dog may be a better choice if you have children under the age of about six.