So, I did my entire C25K program running on the treadmill in my basement. It was safe, the speed was controlled, and I could get more comfortable with my abilities that way. The benefits of treadmill running are very easy to understand and I don't need to spell them out here.
Since then, I've done a couple runs outside. Let me tell you -- it's a night and day difference. There's a certain confidence you get from saying, "look, I can run for 30 minutes straight." But the confidence of saying, "I can run from here to there, and back, without stopping," is entirely different. It's so much stronger and real.
Granted, there are cars to dodge, mosquitos biting, dogs barking, and all that. But it's worth it.
Today I feel like a fit man trapped with 30-40 extra pounds of fat on him. A few months ago I felt like a fat man wishing he was fit. It's a transformation I am very thankful to have made.