Sometimes, when I talk about something with somebody over email, and then we conclude the conversation in person or on msn, I feel a strange need to send a final email to provide closure to the conversation - something like "so yeah... using three will work. see you on tuesday".
It's weird though, because I know that I'll never see the email again - if I do, it will be because I remember the conversation and want to have another look. Either way I know that I won't have any need for the final message there.
I think I feel as if I should leave a conclusion so that if somebody reads it later, they'll have the whole story. It's just plain odd.