I recently decided to quit a startup I founded after raising about nine million dollars. Quitting meant admitting to professional investors, friends and angels

I recently decided to quit a startup I founded after raising about nine million dollars. Quitting meant admitting to professional investors, friends and angels that I had lost their money. It meant admitting to myself and our team that we had fucked up and miss-executed. It meant giving up on a dream and market opportunity that I thought--and think--is still fruitful. So deciding to quit was very difficult. And in general I'm a pretty tenacious guy, I hate giving up. I didn't have to quit. I could have kept going in some diminished form. But the reason I decided to quit is that I had started to do damage. I was doing damage to my health. I was doing damage to personal and professional relationships. Damage understood not as "pain" but as "an irreparable worsening." So my advice: quit before you start to do damage. I'd say that advice applies to most endeavors. Push through the pain, but quit before the tendon pops.