Thank you everyone, now it makes sense! I will definitely take the time to follow baking directions exactly.

I'd just like to say that I'd like to eat at betteirene's someday...

Baking is more like conducting a chemistry experiment than cooking, which can be much more forgiving. Baking is precise. You can learn a lot about it from Maida Heatter.

I've done the impatient route many times, and I've found that some recipes are more forgiving than others. In other words, some came out great anyway & others suffered. Go ahead & make it part of your trial & error process. You'll find which recipes you can cheat with, and which you have to follow by the book. It's nice sometimes to just throw everything in at once & blend. In fact, I recommend trying Lazy Mary's Lemon Tart on this website, because those are the actual instructions!

One reason butter and sugar are creamed together is to add loft (height) to help the leaveners do their work: Instead of trying to lift a flat batter or dough, creaming the butter and sugar until it's fluffy creates little pockets of air and your cakes and cookies will be taller without losing tenderness. Creaming also allows the sugar to dissolve--grains of sugar don't get as equally dispersed throughout a batter or dough as evenly as sugar that's dissolved.

Creaming is one bit of science, and adding eggs one at a time is another. Here's what Cook's Illustrated says: "Looking into our archives, we noticed that almost all of our cake and cookie recipes that call for more than one egg either add them one at a time or premix the eggs and then add them in a steady stream. We wondered why this extra effort is involved and whether it is necessary. First, we made a batch of our Chocolate Chip Oatmeal Cookies (January/February 1997). When the two eggs in the recipe were added one at a time, it took about 30 seconds to incorporate each into the creamed butter and sugar, compared with slightly over two minutes when both were added at once. While the difference in time might not seem significant, the difference in the finished cookies was. Eggs added one at a time led to cookies that were thick and chewy; eggs added all at once produced cookies that spread, became unevenly shaped, and were not as chewy. We encountered similar differences with our Chocolate Sour Cream Bundt Cake (January/February 2004) and Classic Pound Cake (January/February 2007). In both recipes, when the eggs were added together, it took longer to incorporate them and the cakes turned out denser and slightly rubbery.

The fact is, like oil and vinegar, eggs and butter don’t mix naturally. It’s a matter of chemistry: Butter is at least 80 percent fat, while eggs contain large amounts of water. So any time you add more than a single egg to creamed butter, it’s best to do it slowly to give the mixture time to thicken and emulsify."

One of the neat things about messing around with baking science is that you might discover a a nifty new dessert, like those immensely popular chocolate lava cakes, a happy accident with such a delicious outcome that even Domino's delivers them. A long time ago, Elvis Presley's cook put out a cookbook; her recipe for sour cream poundcake was reprinted in a newspaper, and I made it without creaming everything together--I just dumped and mixed. The cake was really good but it wasn't as tall, and its texture was more dense, than it looked in the photo. The next time I made it, I followed the directions exactly and the loaf matched the picture perfectly. But every now and again, I make the batter without creaming the butter/eggs/sugar and it becomes my recipe for the big soft sugar cookies that we eat with a dollop of buttercream, or that I use for ice cream sandwiches, or that are the base for stack cakes.

Here's to impatience and happy accidents!

Here's a slightly detailed explanation of why ingredients for baking a cake are done in a certain order:
.http://www.deliaonline.com/how-to-cook/baking/the-science-of-cake-making.html
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Not all cakes are done this way, as there are reasons that some cakes require other methods to produce the perfect product. Sponge cakes, chiffon cakes, angel food cakes all have different methods. As you bake, you will begin to see similarites to the different types of recipes and methods for mixing cakes and also similarities in quickbreads and cookies. Most cookbooks will advise you about how to measure the flour, the size of the eggs used, and other methods the author used to get the results that were obtained. You should always follow their method to produce those results. Online, many recipes will only give some of that information, so use the method you find most often works for you..but that comes with experience, and some of that isn't always going to be sucessful! I always find a site that has tested recipes and compare ingredient amounds and methods before using a recipe from a home cook whose recipes I've never tried before. (I'm leary and weary of failure!) BTW...I do use a really wonderful buttermilk yellow cake recipe where you do throw all the ingredients into the bowl and mix them at once! Here's the link:
http://www.landolakes.com/recipe/2501/butter-cake-with-browned-butter-frosting

Agree with above. You may get results by your method but you won't get the best results, the tenderest crumb etc. It really doesn't take much extra time (well, I have a Kitchen aid.)

There are reasons things in baking are done a certain way. Baking is the kitchen version of chemistry lab, and for the most part you need to measure accurately and follow directions for the best outcomes.

Here's what I've found (because I've also tended towards impatience in the past while baking). When you cream the butter, you're kinda softening it where it will better accept the sugar. Once the SUGAR is added you can add the eggs. Sometimes adding two at a time isn't a problem but when it gets to more than that, you tend to mix the eggs on TOP of the butter and sugar because the eggs are more liquid. Being impatient (or in my case, sloppy with measuring as I am allowed when cooking) will keep your ingredients from blending THOROUGHLY and EVENLY giving you pockets of butter or eggs or flour. With baking, you have to be a little better about following the rules (recipe). Maybe someone else will offer a more scientific explanation but that's my take...I'm just a mom that likes to cook but it works for me.