Failure comes in all shapes and sizes.
There are small failures, like the time in college when I had my new girlfriend over for dinner and served her a homemade strawberry milkshake that included chopped up bits of wooden spoon that I accidently blended in. I told her those bits were just strawberry seeds.
And there are big failures, like when I was the President of a mortgage company and lead it into bankruptcy, letting a lot of people down along the way.
But no matter the specifics or scope, all failures are the result of three root causes: lack of strategy, lack of effort, and lack of courage.