Running is not cool.
First, it’s time that you could spend doing other things, like watching TV.
Second, it’s difficult. It takes effort and you get sweaty and grimy.
Third, someone might see you and you might look funny, with funny clothes or in an awkward moment where you almost trip and have to hip and jump and try to avoid falling on your face. Or you could fall on your face and that would hurt.
Fourth, you could get hit by a car while trying to change songs if your iPod started playing something you didn’t want to hear.
Fifth and finally, it will cause you to feel more guilty the next time you eat a doughnut.
And that's why running is not cool.