Here's a question: do you listen to the phone with your left ear or right ear? And are you left handed or right handed? PLEASE COMMENT IN THE COMMENTS SECTION, reporting your preferences, if you'd care to report - I'd be very curious!
I currently have an ear infection in my left ear - it's not painful, but it's like there's an obstructive bubble of tissue blocking the canal and muting sounds. I find it rather uncomfortable listening to the phone with my left ear in this state, and I noticed that when I transfer it to the right ear, it sounds WRONG, different. (Try this yourself before you continue reading, if you want your observations to be unprejudiced by my description of my experience). When listening to someone talk into my right ear, I can make out the words people are saying, but it takes more work to process them; they come from a greater distance, sound less like "speech" and more like "sound," and it's like my brain has to make an extra effort to make sense of them.
This got me thinking about "earedness." A friend I spoke to today says he favours his left ear for the phone, too; he offered the theory that it was an issue of handedness - he's right handed, and so listening to the phone with his left ear leaves his right hand free to take notes and such. A reasonable theory, except - I'm left handed and left-eared, both.
Preliminary forays into "internet literature" on earedness are contradictory - one article says (reflecting the conservative view, and my own intuitive sense of things, given the above experience) that we listen to speech and any fast clicking sounds primarily with our left ears, and long sustained tones (music) with our right. Another article says exactly the opposite; both apparently reflect scientific studies. Neither mentions phones - though if the majority of left-handed people are also left-eared, it would do a lot to back up the former position, and require the authors of the second to do some explaining.
I will continue to look into this...!