Just Do It ---> Or Do Something Else.

If some workout sounds absolutely freaking hideous to you that day, then do something else. You don't want to walk 4 miles? Fine. Pick something different. Do a class, get outside and do some sort of relay/obstacle course that you think up full of different exercises. Bike. Swim. Wii Sports/Wii Zumba. Hike. Playground. Dance. Workout Tape. Walk campus. It's whatever, just don't let that "Dreading the Gym" keep you from getting some exercise in.