A lot, and those things stack up over time. If I finish something today it frees up my mind to think about some other, possibly larger problem tomorrow. Do this enough times and it can be the difference between success and failure. I know people like to think in big black swan moments, but most of life is not like that. Life is about making lots of little decisions that add up over time. The speech from Al Pacino in Any Given Sunday talks about fighting for each inch on the football field and really how it is no different than life itself. Over time those inches add up.

From what I've seen - a lot. You can lose a leading client (or cause huge bump on the road), your marketing plan can fall apart.

It's about finishing stuff today, so tomorrow you can do more important strategical stuff.

Start-up contrary to some of beliefs is not one big effort to reach the summit. It's a series of small wins (and loses) that accumulate. And you need to be accumulating them faster than your money runs out or competition takes the space, etc.