A message that looks fine on a laptop might not on a phone. So test it out before you send anything to a busy or important person. "You always have to take into account that someone will be processing that message on-the-go, in an impatient state, at a glance," said Jocelyn Glei, author of Unsubscribe: How to Kill Email Anxiety, Avoid Distractions, and Get Real Work Done.