can you read this mail? consider what it took to get it to you. how did
that happen?
and then consider the number of messages that fail to be delivered,
or messages that cannot be read properly (because they're not properly
tagged by the sender's MUA, or because the recipient's UA doesn't like
one of the headers on the message), or messages that deliver
viruses to their recipients computer systems, or messages that
resulted in mail loops or sorcerer's apprentice syndrome - because
some MTA or MUA vendor failed to conform to the standards.
as useful as email is, the reliability of email is not even close to
that of snail-mail. and that's pretty sad.
Keith
p.s. though mis-configuration of MTAs and DNS servers appears to be
a far larger source of errors than mis-implementation.