To whom it may concern at Zenimax - I'm certainly not the first one to express this, but I think it's important: Please, please... in the future, please apply planned patches to the server when only a few people are playing, e.g. between 3 o'clock and 10 o'clock in the morning CET (as WoW does, by the way), and with a prominent announcement in the launcher the day before, so that people are prepared.
To be confronted with lots of issues (login problems, vanishing guilds and friends) when one wants to relax and play in the evening is certainly not what you want to do to your customers, patching in the night/morning would give you time to iron out issues cropping up during the day, so hopefully people could have a smoother experience when they log in in the evening.