The trouble with whistlers, in general, is that their whistling generally seems mindless. They just whistle something erratic with no tune. No melody. Many I've heard whistle because they can, not because they should because -- frankly -- they should not. It's like singing. You should have a reason to sing and the song should have a beginning and an ending.
If you've ever worked in an office that required any thinking on your part and someone was an idle whistler, then you'd understand the concept of someone stepping on your last nerve. It's like the "American Idol" auditions with one too many William Hungs trying to sing. It's an out-of-body "ear worm".
Of course, there are people who can whistle. One should not encourage them, however.
