Move Fast and Break Things, Including Your Reputation
The fad motto goes "Move Fast and Break Things". I believe it came from Zuckerberg himself, and is plastered all over the walls at Facebook, right? It might be a great blurb to follow at Facebook (although I don't think it is), but at what costs?
When you break things, you end up with more consequences than broken things. You get broken things and a broken reputation. If you continuosly are delivering broken things to your clients/audience/users, they will likely lose any confidence they had in you to get things right. Moving fast is a good way to innovate, but breaking things? Not so good. I love Facebook for its purpose, but the Android/iPhone apps are frustratingly unstable.
I would rephrase the motto to "Move Fast, But Carefully and Things Might Break, But Not Often". Doesn't quite have the same ring to it, but I think it'll treat you better in the real world. Many non-developers don't understand that there are risks when building the new thing as fast as you can. So no matter how much you try to convey those risks to them, they will still walk away thinking you don't take caution to get things right.