I had 5 years of professional cooking under my belt before I decided to hang it up. I did not go to culinary school but managed to learn from good cooks and chefs, teach myself in my off time and get jobs in progressively better or more diverse restaurants.
Bourdain's Kitchen Confidential paints an accurate picture of the grind and the lifestyle of a line cook which is not to be confused with a chef. Among these titles you have many variations depending on the size of the operation and the preference of the chef in how the kitchen is organized or if it's large enough to do a traditional brigade system. Saute, grill/broiler, garde manger/pantry/fruit cutter, chef de cuisine, chef de parti, banquet chef, soups/stocks, etc....
Depending on where you lie in this hierachy determines the amount of freedom you have in bringing you own creativity to the plate. Typically some people who think professional cooking is for them or want to pursue culinary school may not consider the first few formative years in a professional kitchen or understand the "dues" to be paid before progressing. Don't expect to create your own seasonal menu or weekly specials as a first year grunt. It can be repetative and very stressful at times, but also extremely rewarding and ego boosting when you receive a nice complement or when you crank through 150 covers and you are in the zone the whole time. I miss the adrenaline rush of getting slammed with tickets but being capable of cranking through them with consistency and quality all while laughing and yelling vile obscenities at my co-workers. This type of interaction is frowned upon in my current cubeland existence.
While not as seasoned, my experience is very similar to jazzfood's description in another thread of the harshness of a professional kitchen....but i grew to love it. Shades of the military, uniforms, hierarchy, weapons, sense of battle, etc. There is a definite hard living lifestyle that goes along with professional cooking and it's not exactly family friendly. Not everyone participates, but it's part of what builds camraderie and friendships in addition to the cuts, burns, soreness and exhaustion everyone experiences.
I miss professional cooking all the time. What I don't miss is constantly being broke and working weekends and holidays.