In school, 50% was the average grade. 

In the working world, the average grade is closer to 0%. You can always decide not to show up, or to do the minimum.

60% is much closer to 100% than 0%. With some added effort and process changes, you could get to 80%. If you rescope or negotiate, maybe 80% is acceptable. 

Sometimes, it’s best not to let yourself get a 0% because you’re afraid of scoring a 60%.