Who’s “mailer-daemon”?

Mail Delivery Subsystem <mailer-daemon@googlemail.com>

Who’s “mailer-daemon” – I’d just like to know,

returning my words from where they should go.

Not nice in the least – just turns them around,

no reason is given – just back and shut down.

No “Might you try this” or “Might you try that”,

but rather just rude – somewhat of a brat.

If met face to face – would just have to say,

how would you like to be treated that way?