Seinfeld hated close talkers, and everyone hates loud talkers, especially loud cell phone talkers, but I hate people who don't talk at a high enough level for me to hear.
It's really not tough not to whisper, people. If you don't speak loudly enough, then I can't hear you, and you waste both of our time by making me ask you to repeat yourself. Also you make me feel like an idiot because sometimes I cut you slack and think maybe I just can't tell what you're saying, for some other reason than that you haven't bothered to inflate your chest cavity enough, or whatever.
Don't yell, don't whisper. Moderation can be difficult, but this is an easy one.