Messages w/ No Subject

[Carlos Mennens]

I was wondering how mail administrators using Postfix handle messages
w/o any subject material? I don't know if this is an RFC guideline
that requires email to have a subject but I find it extremely annoying
when email doesn't have a subject. I don't know if that's just
personal preference or if it's an actual guideline for mail to have
'subject' data. Do you guys reject mail if no 'subject' is present in
the message?