Why do I do this to myself?

A few months ago I signed up to do a century, a 100 mile bike ride. At the time, it seemed like a good idea. I hadn't been on my bike for a few months, so I thought it would be a good way to get back in the saddle. However, it's been a rainy spring, and though my intentions were good, I haven't really done much training (or quite frankly, any)... until yesterday. Somehow, my friend and my husband talked me into a 60 miler, a very hilly 60 miler. Though the scenery was absolutely beautiful and you couldn't ask for better weather, the ride was a little less lovely. First of all, we had to get up at 6:45 am to get on the road. I love, love, love to sleep, so waking up before 8 or 9 am is not my strong suit. We ran out of water after about 20 miles, my neck hurt so bad, and when I was about 3/4 the way up the last climb, I crashed. Par for the course. So although I made it, I'm left wondering why do I do this to myself?

The century is in two weeks. Is whatever possessed me to ride yesterday also going to motivate me to head out on the 113 miles then?