I may be the last one on the planet to discover this, but thought I'd risk it and throw this out there :-). I have realized over the years that I subconciously hate reading plain text emails because the default Outlook plain text font makes the email so visually unappealing. I found that I would read little of any plain text email and delete it quickly. I would occasionally get burnt for missing something important.
I recently discovered that it's easy to change the plain text font for Outlook under Email Format options. I set it to Calibri. Life is much better :-).
It's the little things that count :-),