Baby clothing sizes, wtf!?

Who comes up with clothing sizes for babies? I mean really! WEB is a little over 3 months old, but he's very long and kind of skinny. Most of his clothes are too wide and too short. He grows out of the length far faster than he grows out of the width. There are clothes he has by Circo (from Target - aka my 2nd home) that say 3 months and are way too big. He can still fit into some of the newborn sizes from them! What the...? The only clothes that seem to fit him perfectly are by Carter's, but it seems like he grows out of them super fast.
The sad part is that sometimes I don't really notice that he's grown out of things until I already have it on him. Then, I've already fought with him to get it on and don't want to piss him off again to change his outfit, so that day (or night) he wears something that is just a little too small. It's actually kind of funny when he throws his little tantrums and does the "stiff as a board" move and the neck of the shirt scoops down like a low scoop neck shirt.

Another issue is the size of his feet. When I was pushing him out into the world, my Dr. made a comment about how big his head was (like I didn't already know that!), and then said how big his hands and feet were. For a Dr. to make a comment about the size of his hands and feet seems like a pretty big deal to me since he sees lots and lots of baby hands and feet day in and day out. This means that the cute little baby shoes that people bought him don't fit and never did fit him. Also, I feel bad because some of the feet in the feety pjs are too small. So if the pjs fit him length-wise, they probably don't fit his feet.
I guess WEB has as many sizing issues as any other person when they're buying clothes. The only difference is that he doesn't seem to care one bit. I guess that's a beauty of his situation. Now if only I could be as easy going about my clothing issues... ;)