"Your best was not good enough" is a common phrase we hear bosses tell their staff. It's also something we tell ourselves often too.
"I tried my best" puts a focus on self and our limited ability to carry out specific tasks. Our best is simply determined by our level of motivation, knowledge and skill.
However, when we choose to stand on the shoulders of giants, we're able to leverage their own level of motivation, knowledge and skill to do what we want to do. Imagine being told to look at the top of a tall building and identify how many birds are perched there.
If you're on the ground, there's no way you can carry out that feat. That's your best. And sincerely, you've tried. But if you decide to climb to the top of a taller building just beside it in order to identify the birds, then that's leverage. That's standing on the shoulders of giants. Your level of best becomes insignificant. Even a person with an incredibly low IQ would be able to identify the birds as long as he climbs to the top of the next building.
This is what God wants for us. And He's simply saying, "regardless of how stupid you think you are, I have given you a giant (my son) on whose shoulders you can climb. But you have to receive Him first so you know where He is. Then, you'll be able to climb and do ALL things because He will strengthen you." (Phillipians 4:13).
Go into your day with that mindset. Your work must make sense today.