I know this was (most likely) sarcasm, but I was talking to my uncle (at thereapist) at a family gathering about two weeks ago, and based on some of the things I was describing, he sent me the list of what they look for in Adult ADHD -- and although multitasking is the useful benefits, there are enough other factors that are common, that it can outweigh any benefits. If you look at some of the common indicators, you'll see that quite a few of them are not particularly useful in the long run.

Doing lots of tasks at the same time is of no use of if none of them ever get done.

Update -- It'd probably help if I actually gave some advice -- keep a to do list. I keep mine on a small white board. I try not to take on any more tasks if the board fills up (which is about 12 to 18 things, based on the size of my writing and the board). I find it useful to make sure that I don't lose sight of all of the tasks I have assigned, and not to get so many on my plate that none of them get one.