Because your framerate skips slightly. It's difficult to notice, but I get random misses when my computer's low on memory, making the arrows jump almost unnoticably. Try closing any//all unused applications before you run stepmania, but a restart usually does the trick for me.
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[quote:8b1ee61c71="rampage
in oct '04"]
I'm sure if it was sold for profit, Konami would clamp down on it
(I'm sure it's a matter of time before they clamp down on ITG).[/quote]