[oblio]

Lesson I learned early in my career, luckily not on my own: never write something that you really don't want someone to see, especially bosses and clients and especially swearing.

Mails are replied to, mails are forwarded, long chains of emails happen, your stuff gets out.

A colleague at one of my first work places made fun of a client. 10-20 replies and forwards later, his mail was sent to a client. Luckily I think his message was buried too deep in the resulting mail and the client didn't see it.

I did, though, as did several people from my team. We didn't say anything but we all learned a lesson that day :)

[isostatic]

This type of thing was always inevitable from the day top-posting became acceptable (and pretty much mandated by the email clients)

Before then, you would reply to points in line and trim unneeded information. The entire conversation wasn't bolted on to be ignored by 99% of people.

[oblio]

It would be harder, but still possible. The "trimmer" could keep the offensive bits in, causing even more damage because of the higher visibility.

Just don't write offensive stuff :)