Ever wonder why people leave this site and don't say goodbye?

I think there are a number of reasons people leave without a good bye.. I try not to put too much stock in it. I know I have done it myself.. either a phone call or a visitor. could be anything.. really.. and by the time you come back the person is gone.. or like me, I do a lot when at work and I can only talk on breaks.. so I'm apt to leave without a goodbye as I need to leave at certain times and I get too busy talking to keep track of time.. and before you know it.. my break is over :).