Listened to a ranty discussion by relatives of in-laws about how email is useless and nobody can deal with it, when there's a dozen per day. Pretty soon you have an inbox with thousands of emails, and communication becomes impossible.
Didn't want to get into an argument, and so I kept my mouth shut.
#GTD and carefully trimming mailing list subscriptions works for me. I don't have inboxes with thousands of emails.
At one point I processed about 4000 mails per day, after spam filtering.