Sometimes the internet is slow. Sometimes my server is slow. But when you click on the "Submit Message" button repeatedly, not only does it actually slow down the response, but it sends your post on each click. Traffic on the internet gets very slow at certain times of the day and if everyone on the internet sent the same data repeatedly whenever it got slow, it would bog it down even further. And I'm sure it looks rather embarrassing to see your name on a half dozen identical posts all dated within the same minute.