a brief look inside my head
I have selective hearing. Some people say this about themselves as a joke, but for me it's 100% true.
If you are having a conversation with me and there is a television turned on in the background with some noise coming out of it - I will have a problem understanding what you're saying.
If you attempt to speak to me while I am watching a movie, I cannot concentrate on the movie and what you're saying at the same time. I have to pick one or the other and choose which to listen to. The only time it's okay to speak to me is if I've seen the movie before, because otherwise I am completely engrossed in the film.
If I am driving somewhere that I haven't been to before, and you attempt to speak to me while I am concentrating on the road, this breaks my concentration and I will have to tell you to clam up. However, if it's somewhere I have been to before, then it's okay to speak to me while I'm driving.
I cannot read a blueprint. If you give me a two-dimensional representation of a room layout, I have a very difficult time translating that into three-dimensional reality. This is part of the reason why mall directories (the thing in the mall where it says "you are here") confuse the crap out of me. I have to look at the map, look where I am, look at the map, look where I am, then repeat this several times before I start walking.
Oddly enough, I can easily understand geography. This is due to my heavy GPS usage. Most people cannot understand "Get on the highway in the westbound direction". They'll be able to understand north and south easily, but not east and west. But if you tell someone how to get somewhere by an interstate exit number (such as "get off the highway at exit 39"), that processes much easier for most people.
the trained brain
My brain is usually only able to multitask if I'm doing things I've done before. A simple example is operating a microwave. I can talk on the phone and operate a microwave at the same time. But let's say I'm on the phone and trying to figure out a new cell phone. Can't do it. I have to place 100% concentration on learning that phone first, or put it down and learn it later to concentrate on the phone conversation.
Once my brain is trained to learn something, I can then do that whatever-it-is and do something else at the same time, else I can't process it.
slow or just different?
For the longest time I honestly thought I was just slow, i.e. someone who can't think as fast as others.
This is not the case because I can operate very complicated technology blindingly fast while others would be left permanently confused. Why can I do this? Because my brain gives 100% concentration to the technology in question, processes it and understands it quickly. Other people are thinking about different things while trying to learn new things - therefore slowing them down.
And how is it I can be so creative with things like music? It's because my brain has amassed a ton of music knowledge over the years, takes inspiration from tons of sources, and allows me to create something that is uniquely "me" in the end. Others don't retain, rather, the creative process is limited by only scratching the surface of what they could truly do.
So the answer is: Just different.