Asking of what pleases God the most is difficult to attest to. But according to the Bible, the only One who pleases God the most is the Son. It is only the Son that the Father attest to that with Him, he is well pleased. This was the testimony when the disciples where with Jesus Christ at the transfiguration. The Lord Jesus Christ alone is the one who has ever received such testimony from God.
When we consider what Jesus did according to the book of Philippians 2, we see the way the that he humbled himself to fulfill the Father’s will. Though he was God himself, he humbled himself unto death on the cross. He didn't that he was being rubbed of his position but he willingly led down his glory and came in the form of sinful men so that he might do the purpose of God which was to serve humanity.