The taper time in training for a long distance race, for me, is filled with anxiety. When your building up your distance running, it seems you are focused on that weeks long run -- now you are slowing down with less mileage. The taper also forces you to think about something that won't happen for about three weeks.
The tough thing for me is NOT to run. Honestly my mind says do more, but I know it's about race day. It is time to heal, eat the best you can and REST. Work on actually getting sleep. Think about the food you ingest (remember garbage in garbage out).
Perhaps the toughest part of the taper is the waiting and second guessing. Everyone feels they may not have done enough to get through the race in the time they set for themselves. For me I am competitive with myself. I always want to do better than before or it is considered a failure. This is not the most positive way to think I admit. However it does give me that push sometimes to move.
Another aspect of the taper process can be the little aches and pains that crop up. For me I have had muscle tightness and ankle soreness that seem to have come from no where. As I ask running friends and looked around message boards, this seems to be a trend for most runners. The body starts to heal and giving it time to heal before the big race will only make you stronger for the race. The trick for me is not to worry about every little feeling of soreness as a debilitating injury. (Although if the pain you feel is changing the way you run, than please rest and have it checked)
I do believe this -- the experience of training for a Marathon is not one to just dismiss when you are tapering. The discipline, the time it takes away from other things. Waking in the morning before anyone else just so you can get that run in. After all of the miles logged without injury is an accomplishment in an of itself.
So with one week left and my mind now focused directly on the race. I will: Think about eating right, plan out what I need, and sleep! Even if I can't break the 3:59:59 mark, I sure hope to beat last years 4:14:36 mark. We will see.