🚀 go-pugleaf

>Until then most users don't want to do some arithmetic just to see when
>a message was sent or when it arrived.

To quote from the message to which you're responding:

>The user interface should translate if appropriate -- *it* knows
>about arbitrarily messy local conventions.

so Henry was not saying that users should have to "do some arithmetic
just to see when a message was sent or when it arrived".  He was saying
that the *user agent* should do that arithmetic.

Unfortunately, many user agents don't do so, so the question is how
quickly they'd get updated to do so (or how quickly those that don't
would be discarded) if lots of messages started having header times in
GMT.

If it happens quickly enough, no problem; if it doesn't, such that the
effect of going to GMT is that users *do* end up having to do that
arithmetic, the proposal may well not really make life better for the
end user.  (An unfortunately tendency, at times, is to contrast
alternatives A and B under the assumption that some C could exist that
makes one of the alternatives better, when that C doesn't, in fact,
exist yet; a bird in the hand is worth two in the bush.)