Are mail servers just stroppy teenagers?

This is an automated response from a Yahoo mail server, which my friend received after trying to email me. I was captivated by the seemingly friendly but curt series of messages, which kinda builds images of a stroppy teenager.

From: MAILER-DAEMON@yahoo.com
Date: 12 June 2007 00:21:13 BDT
To: a-n-other@yahoo.co.uk
Subject: failure notice

Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

:
Connected to 195.224.48.121 but greeting failed.
Remote host said: 421 six.mx.123-reg.co.uk: Too many concurrent SMTP connections; please try again later
I'm not going to try again; this message has been in the queue too long.

--- Below this line is a copy of the message.

And in case you wondered, yes my mail forwarding hosting service is failing once again.

It's funny, 123-reg often get blamed for failures, but maybe that's because there is no-one else to blame? sigh.