Here are the real stages of development, as recently experienced by myself, husband and boy.
Stage 1: The Sleepy Bundle.
This stage is very short-lived, usually limiting itself to the hospital duration only. It's characterized by long stretches of sleep, punctuated with short stretches of nourishment or digestive-system testing. This stage allows new parents plenty of time to rest and get charged up for what follows, though they nearly always squander this time in admiring the Sleepy Bundle.
Stage 2: The Angry Blob.
Shortly upon arrival home from the hospital, the Sleepy Bundle metamorphoses into the Angry Blob. Scientists are not certain how the Sleepy Bundle is sentient enough to realize that the supportive nurses at the hospital are no longer around, but it's incredible how accurate this timing is. The Angry Blob has a lung capacity approximately seven times that of the baby in its former stage, and makes use of it frequently. It's normal for new parents to become terrified of their own baby while he or she is in this stage, and begin to tiptoe around the house during the rare moments of quiet that present themselves, out of fear of awakening the Angry Blob. This stage usually lasts approximately until the baby's eighth to tenth week.
Stage 3: The College Roommate.
At some point, the Angry Blob bestows its first smile upon its parents. When this occurs, the baby's parents usually forgive all Angry-Blob outbursts that have preceded the smile, and enter into a new relationship with the baby. They will tolerate long stretches of indifference, relish the occasional grin, and clean up the baby's messes and various odors, which is why the stage is named as it is. This is known as the College Roommate stage also because the baby's parents will consume an inordinate amount of delivered pizza, out of proportion to that of any healthy adult diet, due to the sheer convenience of the meal. The College Roommate stage usually lasts until about the baby's fifth or sixth month.
Stage 4: The Benevolent Dictator.
Once the baby passes into the sixth or seventh month, smiles and laughter become more frequent, and the baby even learns a few useful party tricks, such as waving "bye-bye," blowing kisses, or creating farting noises on someone's bare arm or cheek. Because parents and their circle of family and friends will do anything to receive the favor of these small performances, the baby soon learns to lord these behaviors and use them at the most opportune times (usually to extend playtime, delay bedtime, or receive a tasty morsel). While this is clearly manipulative, most babies have learned to smile so charmingly that no one minds this arrangement.
Some babies are still in this phase at their first birthday. However, as is becoming apparent with boy, others may enter into a fifth stage.
Stage 5: The Best Friend (a.k.a., The Siamese Twin).
As the baby develops a sense of self and identity, he or she also realizes that parents are separate entities as well. Therefore, whenever the parent who is present attempts to leave the room (for such selfish reasons as relieving his or her bladder, or going to work to earn money to make the baby's LIFE POSSIBLE), the Best Friend cries real and terrified tears at this seemingly unnecessary and traumatic separation. Parents find themselves resorting to ridiculous behavior to avoid the tears of the Best Friend, who now is carted along everywhere, such as to Wal-Mart, the grocery store, Home Depot and the restroom (thus earning the alternate name The Siamese Twin).
Though we have not yet experienced the stages past these, we hear from friends that the second year holds such exciting new developments as The Prima Donna, who throws tantrums in public at the slightest provocation, and The Contradictor, who will disagree with any idea just for the pleasure of saying, "no."