I'm actually stuck working from home, more than not, and not entirely by choice. My health has become an impediment to my working in an office full of people due to chemical allergies, so I have no real alternative but to telecommute most of the time.
I've found that since I started telecommuting, I'm beginning my day at least two hours earlier, and I persistently check my e-mails and watch the systems I administrate up until my wife drags me to the table for dinner, and then after dinner, then for another hour before nodding off at night. I'm not paid any more or any less for the extra time I put in, and I don't complain about it, either.
I'm sure that I'm not the only who does this.
I agree that the majority of telecommuters--that are worth employing at all--are probably more ambitious than the average Joe who sits in traffic for at least an hour to and from the office, and can't stop thinking about how long off it is until 5pm each day.