You might as well curse your friends as wake them up early in the morning with a loud greeting.
So what’s the problem? At the very least, the gregarious friend is showing a deplorable lack of common courtesy. Even if they means well, their timing is off by about two hours. Harry Ironside calls this behaviour “utterly obnoxious.” Such a person is tone-deaf to the delicate sensitivities of friendship. There is a proper time for everything—including hearty greetings.
No matter how cheerful or well-meaning the message, if a greeting is obnoxious in its volume or timing; it is not a blessing but a curse. A detraction, not the delight it was intended to be.