If you don't feel like working out fake like you do until you get down there and actually feel like it. If you don't feel like being happy smile and fake it until your are laughing and actually happy.
When things look bad and you are frustrated, upset, and just not feeling happy find what you can be thankful for. If your kid is crying and getting on your nerves be thankful you haver a kid to do that. How many people don't have one.
Trying new classes at my gym keeps me going. I get to know the people in them and we have fun while burning those calories. I also get to try new things I may not have heard of or new. The trainers explain what we are working out and how it benefits me.