I'm the kind of person who just says whatever comes to mind. Don't get me wrong, I think everything through before I type. I just like to say whatever and do whatever. If I'm bored with what's going on in a conversation with my friend, I'll go BLAH. If I'm hyper, it'll be ASDF. And then there's everyone's personal favorite which I say when nothing's going on, when I have no idea what to answer, or just ... whenever. XD You may have read it in this thread already, but I'll repeat it.
ASODIGH!
Don't get it? Neither do I, or any of my friends for that matter. I've always typed out the string of letters almost in that exact order and my friends have caught on. At first, I didn't even know I'd be typing that. I'd just type AOSDIGH and enter it. The O and S or the G and I would be mixed up at times, but it was close. After entering, I'd look at what I typed and say "wow, why do I always type that?" Once after I typed it on skype, my friends asked me what was up with that and told me that they noticed how it was always there. Since then, it's just kind of stuck with me and now my friends even use it. XDDD