Getting email right is an essential part of working today. But there are still people who can’t hack it. We asked agency execs what their biggest email pet peeves were. Some, like Sean Cummins, hates the “xx” at the end of business emails. Others, like MRY’s David Berkowitz, can’t stand follow-up emails with 10 more emails. And then there are people who wish clients wouldn’t cc them on everything.