Updated: Jul 14, 2021
Two problems with this:
In most areas of young adult lives, they haven't pushed themselves enough to know what is their "Best".
Even if they know what is their best, their best may not be enough.
Good Intentions, but...
While reassuring, telling young adults that doing their best is all anyone can ask of them can lead them to use this adage as an excuse to prematurely curtail growing and working hard.
Most young adults have not lived long enough to know their limits in most domains of their lives. A few might have a glimpse of their best, if they have achieved world-class excellence in a domain such as swimming, chess, violin, karate, math.
Most young adults have untested ideas of what constitutes their "best".
Moreover, in college and career young adults will face intense competition. What if their "best" isn't good enough? Young adults should not expect the real-world (employers, faculty and associates) to accept their "but it was the best I can do" as a substitute for achievement.
Employers are extra-ordinarily demanding of their employees, because employers must satisfy extra-ordinarily demanding customers to survive. Ask yourself if you have ever shopped on-line at Amazon for example and selected a product based on the vendor's "best effort" rather than on demonstrated achievement. Most of the time, we choose the highest quality product with the best service for the lowest cost.
If a particular vendor's "best effort" isn't good enough to satisfy us, then either that vendor improves their "best effort" or becomes irrelevant.
Ask young adults, "what makes you think this is your best work?"
Ask young adults, "aren't you curious to explore how good you might be?"
Ask young adults, "what if your best isn't good enough for __________?"
Instead of encouraging young adults to "Do your best" let's encourage them to "Do your better." This new phrase implies that the young adult has room to grow and ought to improve continuously.
Do your Better (Ask More of Yourself)