We've all done it in our jobs. We write an email, maybe copy a number of people, and proceed to work out the details for a specific aspect of an event or project. It usually leads to several back and forth emails, questions, answers, etc., when the easiest thing to do would have been to simply walk over to that person's office or pick up the phone and talk to them. So why is it that we don't just take the simple route? CYA (Cover Your ***).
We've all been burned at one time or another. We go over things with people, agree on what's going to happen and who's going to do what, and then BOOM! Someone throws us under the bus. Someone basically saves their own skin when something doesn't go as planned, and we don't have anything to show what was agreed on. From this point on, we put everything in writing. We shut down on verbal communication and rely on written communication.
The easiest way to work with other people, and the best way in my opinion, is to talk to them, whether face to face or on the phone. I understand the need to CYA. I put things in writing, too. What I would recommend, though, is this: develop relationships with people. This is an important part of any job. Talk with people to plan and work out the details. After the meeting, send an email (a single email) summarizing the details of what was agreed on. "Per the discussion we had about staffing/registration/sponsor deliverables/whatever...." This email will serve the purpose of documenting the details and making sure that there isn't any confusion.
This is advice I've given to the people who currently work for me. We had some contentious times between departments in the past, but the relationships have gotten a lot better, simply by increasing the direct communication. Relationships are personal. Email, too often, is not, and if that's the only way you're communicating with people, it could make your job all the more difficult.