I prefer to read emails in plain text. Having to turn on html viewing is a pain. I'm tired of companies that send me noncompliant multipart/alternative emails with both text/plain and text/html portions, but where the text/plain portion is blatantly NOT the same content as the text/html portion, but rather a crippled version that lacks critical text, or where the plain text is so badly rendered that it is illegible. The most common case is where an email will state something like "click here to ...", but omits a URL in the text/plain portion; then there are the companies that send html markup in the text/plain portion (making the real text hard to find), or which smash words together because a newline in the html version was not converted to a space in the plain text version. But there are also some senders out there brazen enough to make the text/plain portion read along the lines of "Turn on html view in your email client to read this message" which is completely different from the text/html portion, or even send a text/plain version that is completely blank. Obviously, convincing mail senders to obey RFC 1521 is the ideal solution, but that's not happening any time soon, so we need Thunderbird to work around sender's stupidities. My current workaround is to install the "Show All Body Parts" add-on, and then toggle between Menu->View->Message Body As->{Plain Text, All Body Parts} and back when encountering a broken email. But that's a lot of clicking, and viewing all body parts kind of defeats the purpose of multipart/alternative as I'm forced to scroll through the text/plain half before seeing what the sender intended in the text/html half. So in the meantime, I'm looking for a configuration knob that will tell Thunderbird that I still want to view my mails as plain text, but that if the sender used multipart/alternative, then I want a plain text rendering of the text/html portion (and NOT the plain/text portion as-is), as Thunderbird's html->text rendering is often-times light-years better than the vendors, and at the very least is likely to list URLs in a form that I can actually click and not smash words together, instead of whatever botched plain text rendering the sender's bad software created. Even better would be a knob that I could set per-sender (emails from senders on my whitelist show the text/plain version, because I know they send a decent rendering; a blacklist can mark senders known to send botched text/plain portions where the plain text downgrade rendering of the text/html portion is going to be a better presentation).