Dove v. Rose Acre Farms 434 N.E.2d 931 (1982)

Dove entered into a bonus system with his employer, including working 10 weeks straight without being late or absent.
Dove’s performance was perfect for 9.5 weeks.
Dove was sick for 2 days and so lost the bonus.
He sued arguing, essentially, that his performance was nearly perfect and his failure was out of his control.

Can you have substantial performance of an entire contract where the contract stipulates you must complete in full?

The Plaintiff knew the terms of the contract when he agreed to them; if he thought they were unnecessarily harsh he could have refused to participate, but he didn’t.
Fighting tardiness and absenteeism was a central theme of the bonus program and so it cannot be removed
There was no fraud on the part of Rose Acre Farms that would make the contract unfair.
You cannot use “impossibility” to sue for the value of the contract, only against paying damages.

This case is a demonstration of the principle that you cannot have substantial performance,