Just because something doesn't do what you planned it to do doesn't mean it's useless.

I never failed once. It just happened to be a 2000-step process.

I never did a day's work in my life. It was all fun.

Restlessness is discontent and discontent is the first necessity of progress. Show me a thoroughly satisfied man and I will show you a failure.

I haven't failed, I've found 10,000 ways that don't work.

Opportunity is missed by most people because it is dressed in overalls and looks like work.