That being said, there is a "what" that is worth sharing about! But it's not our accomplishments. Your accomplishments and mine alike, will never amount to the accomplishments of Christ - no matter what. Jesus Christ came to live a sinless life in a sinful world just to take on the wrath we all deserve for our sin. What a Savior! My college degree, happy marriage, close friendships, or career in full-time ministry cannot compare to what Jesus Christ has done for the world. And please don't be offended, but neither can yours. Nobody's "what" will ever top the accomplishments of Jesus Christ's!
Boast about Him, not you. It is so easy to begin rambling about all that you are doing or have done. But what if we refocused on the utmost important achievement? Are you more proud of who you are or who He is? What if we were so captivated by Jesus and less proud of ourselves, that we boasted in Him rather than us? If we remember that, at the end of the day, what He's done is eternally more significant than any "what" in our lives, it shouldn't be too much of a challenge!
"Thus says the Lord: “Let not the wise man boast in his wisdom, let not the mighty man boast in his might, let not the rich man boast in his riches, but let him who boasts boast in this, that he understands and knows me, that I am theLord who practices steadfast love, justice, and righteousness in the earth. For in these things I delight, declares the Lord.”" - Jeremiah 9:23-24