My wife was an office manager at an Audiologist's office. She has some crazy stories about that. Unfortunately, lots of people who don't hear well also shout all the time. Just part of doing business. :-) (Edit: She corrected me. SHE had to shout all the time.)

Also, many people purchase hearing aids and then never wear them, because they can't stand the "new" influx of noise and most of it doesn't seem necessary or even desirable. So they effectively spend the money and then feel ripped off, in a sense. Or their spouse, who paid for the hearing aids and basically feels like they burned up thousands of dollars for nothing, is very upset.