Why do you call me good?

Mk 10:18 is a unitarian prooftext. Here's a helpful analysis:

Jesus uses questions and riddles to lead his audience into the mystery of who he is. Cf. Tom Thatcher, Jesus the Riddler: The Power of Ambiguity in the Gospels (WJK, 2006). 

Jesus ends by telling the rich young man that the "one thing" he still lacks is to sell all he has and follow him. This ending is essential for unlocking the riddle of his words. Yet it is constantly overlooked by those who claim Jesus is denying that he is God. After making his declaration about the goodness of God, Jesus does something stunning: he adds a command to follow him to the obligation to keep the Ten Commandments. In a 1C Jewish context, this would have been shocking. In Jewish Scripture, the Ten Commandments are written by the very "finger of God" (Exod 31:18). Yet here Jesus is adding the command to follow him as if that was on par with keeping the commandments.  As Simon Gatherole writes:

What is most striking is that having established the one good God as the one who defines what is required of human beings, in the final analysis Jesus is the one who defines what is ultimately commanded…If God alone is good and able to give commandments, then Jesus does as well. By implication then, he is also good. And he is good not in the sense implied by the rich man, but in the absolute, divine sense used by Jesus himself. Brant Pitre, The Case for Jesus (Image 2016), 151-52.