I wouldn't go so far as "everyone's life is slightly prettier". Certainly I get a lot of ghastly-looking mail through my text-format, when it's all links I can't follow and bold and underline and half the time I delete it. But I get much more offensive email at work, using my HTML reader, with changes of font for no good reason, and eight different colors which convey no logical content and half the time don't have any contrast. HTML email allows people to indulge their worst inclinations to be "creative" without any kind of requirement that form matches function.