After working through a technical problem the week before last, the subject of system transparency came up, and the support rep suggested that I post about it here. Basically, the game client spontaneously stopped being able to contact the login servers, leaving me unable to play. After a few days and several messages back and forth with support staff, it turned out that the problem was not on my end at all. This was a rather frustrating waste of time, both for me and the support reps.
My suggestion is that ArenaNet operations staff start communicating with the rest of us (both their customers and their support staff) about changes that could cause or fix network issues. Just something simple like a network events page, preferably with a syndication feed for my RSS reader, to let those who are interested know when things are being changed or problems have been found or fixed. My ISP does this, and the transparency is a rather effective way of keeping customer satisfaction up when things break.