Calling Mail from command line - What works and doesn't

I had some trouble recently calling /bin/mail with -s for subject, quoting the actual subject in single or double quotes, and passing in the destination addresses in a shell / environment variable. So, here's the truth table of what works and what doesn't.

# Explanation of what works and doesn't when calling mail with various params:

#[krice@test1 krice]$ EMDEST="Kevin@justanyone.com"
#[krice@test1 krice]$ ps | mail -s 1132 $EMDEST          OK
#[krice@test1 krice]$ ps | mail -s 1132A "$EMDEST"       OK
#[krice@test1 krice]$ ps | mail -s "1132B" "$EMDEST"     OK
#[krice@test1 krice]$ ps | mail -s "1132C" '$EMDEST'     BAD
#[krice@test1 krice]$ EMDEST="Kevin\@justanyone.COM"
#[krice@test1 krice]$ ps | mail -s "1132D" '$EMDEST'     BAD
#[krice@test1 krice]$ ps | mail -s "1132E" $EMDEST       BAD
#[krice@test1 krice]$ EMDEST="Kevin@justanyone.COM"
#[krice@test1 krice]$ ps | mail -s "1132F" $EMDEST       OK