Authors:

...it's easier to hold to your principles 100% of the time than it is to hold to them 98% of the time.

Harvard Business Review, Michael D. Watkins, Clayton Christensen, Kenneth L. Kraemer (2015). “Harvard Business Review Leadership Library: The Executive Collection (12 Books)”, Harvard Business Review Press
...it's easier to hold to your principles 100% of the time than it is to hold to them 98% of the time.