There is a big difference between a solution that is a perfect fit, and the one that is ‘good enough’.
Which one do you need?
Contrary to the popular rule of 80⁄20 and a lot of advice telling you that getting to 80% fit is all that matters, in certain cases it is better to walk an extra mile. For example, if you are working on mission-critical system that operates in a healthcare environment, you don’t want to ignore 20% of the remaining requirements.
As with any other rule, I use 80⁄20 sparingly, and always evaluate how far is ‘enough’ before declaring it ‘good’.