What irks me about Unix mail

In my posting called Unix Bugs vs. VMS Bugs I deliberately stayed
away from technical differences between Unix and VMS, although
some of the people who responded didn't follow suit.

In this posting I'm not staying away from the technical differences
between Unix and VMS. I want to discuss something that has caused me
much grief in my attempts to reply to people who have sent me
responses to my postings. This problem is the absence of routing
by the mail system.

Even though I'm a VMS manager, I'm just a Unix user. I don't have the
same technical knowledge of Unix that a Unix manager has and, what's
more, I don't want it. On Unix I want to be a user like everyone
else.  Therefore, I don't think its unreasonable to expect that when
I get mail from someone, I should be able to fire up the reply option of mail
and know that my response will get to them. After all, their message
got to me OK. Most of the time, when I do this I get a message from
some program (you never know on Unix where messages come from) telling
me that the destination was unreachable. This is after I spent valuable
time creating a message whose wit and insite would completely
overwhelm (sp?) the person who is to receive it. On VMS I know as
soon as I get the prompt for Subject that the destination is reachable.

In my ignorance I may be doing something wrong. If so please correct
me. Otherwise, I wonder if Unix is really the networking system is
claimed to be.

I mean this posting as constructive critism.