It's such a relief to know that other people do this. I have been counting letters in sentences for as long as I can remember and it is instantaneous for me as well. I kept it to myself for years, but recently have told my friends and family about it and they get a kick out of it. They will look at me and say a sentence and I will give them the number of letters in the sentence the second they are done...they think it's the coolest thing. It has never really gotten in the way of my day-to-day life, but there are other things that get on my nerves. Such as, when something has a volume control that reads out with a digital numeric display, the volume must be on an even number or a multiple of five, or it freaks me out. If someone put the volume on an odd number I try to change it inconspicuously, but people always notice and make a big deal out of it, and I think my friends do it just to piss me off now. I also count the number of stairs when I am walking. If there is an odd number of stairs (or not a multiple of five) I will avoid those stairs whenever possible, thinking that the person that put them in did it in a hurry and should have put in an even number, so they are not safe. I also find myself constantly lining things up so they are in some kind of order; I don't like disorder. I wish I was compulsively clean, because even though things are in order...I let things get all kinds of dirty and that doesn't bother me at all. It feels good to get these things out and know that I'm not alone.