"Avoid instant messaging at all costs" is definitely good advice. I usually forget to take three breaths before answering there, but I usually remember before I answer an email. Plus, I have GMail's "undo send" feature enabled so I have a few more secrets to repent before my message cannot be untyped.

+1 to not logging on to the company’s IM. Emailing somehow feels more ‘persistent’ so it’s unlikely that conversation like the one above would have happened in an email thread. Or, people have to come and talk to you in person; in which case they will probably think twice first and maybe solve the problem on their own in the process.