Sometimes it would drive me crazy because I would shout at him, "You know what I mean, just do it!" But really, as it came to be, he didn't know what I meant, and as the years went by and I learned more about Asperger's, I realized that he didn't understand all sorts of things unless I spoke in exact literal terms.
As a person with Asperger's, they don't understand the hidden meaning behind things said, or they don't understand sarcasm or even funny phrases than seem understandable to others.
For instance, I once told MJ that his aunt "lost her voice" and he was horrified. I had to explain what I meant. Another time someone said "that girl was smokin' hot" and I had to explain that she wasn't on fire, but that they thought she was cute.
As far as understanding the hidden meaning, this is the toughest one. When in first grade, I met with the teacher for the first parent/teacher conference and she showed me how MJ was failing excellerated reading because he hadn't taken any tests. She said every time they finished a book they were supposed to take a test on the computer, but MJ wasn't doing this, he was just reading another book one right after another. She said when she asked him why he hadn't taken any tests that he said he was just excited to read the next book. And so he continued to not take tests.
This is when I really was awakened to how much I needed to be super exact with MJ. He didn't understand the teacher's "why haven't you taken any tests?" question to mean anything but "why", when the real meaning the teacher meant for him was "you need to take a test now, and after every book you finish reading".
I had to explain to the teacher that she had to tell him exactly what she wanted from him and not ask questions to mean something he needs to do.
It's like with most kids you could say something like "gee, I wish somebody would help me clean up" or "maybe if you wanted to be nice you would play with your sister" and they would understand to help you clean up or play with their sister, but for an Asperger kid, they don't see any hidden meaning, they just hear you talking to yourself or making a comment that doesn't really affect them personally.
We learned that if we wanted something done that we had to directly and specifically tell MJ what it was that we wanted. Never ask rhetorical questions, and never assume that he knows what is expected of him unless you have directly explained it to him. Telling an Aspie child something like "Now, remember we are in the library now, or remember we are at church now" will do nothing for them to understand the real meaning of "You need to be quiet now." You must just say what you really mean.
And really, wouldn't life be a lot easier if we all just said what we really meant without this beating around the bush thing? Let's just get to the point!