Dude, without a gym, life would be horrible. Too many slow people who can't run or jump or dance, or have fun because they're all too busy wheezing, and trying to breath for survival. Remember Zombieland? Cardio guys, the zombies would win without good and decent cardio.
I'm glad I had tennis in High School, and Badminton/Bowling in College to keep me going and skinny every day. I feel more agile, alive, and I feel 100 percent better after I exercise. Oh yeah, I was 190 pounds in December, and I made a New Years eve resolution to lose weight. Sure enough, I did, and I lost 30 pounds during my job as a Liberty Tax waver(I wave signs at cars, and they honk and etc...) I hope to lose ten more pounds sometime in the next two weeks.