My vote is fora break in routine being most disruptive to me.

It's funny, now that I've been back as a student for so long the summer really bothers me. Even though school is stressful, the routine of going to class, having projects to work on, etc., makes for a nice pattern to life. When summer hits, I might be taking classes, or I might be doing independently study, but the lack of routine takes its toll.

What's funny is that a good prof friend of mine from my undergrad years feels the same way. There's something about the routine of the fall and winter semesters that helps one structure things. I'm pretty sure he's an OCD and anxiety sufferer as well...which means we're good friends, but he would be a terrible supervisor for me.

Sleep I can do with or without...I don't mind naps, though I don't like when they get too long. I also probably work too much, since I let day spill into night and keep on working away.