"Christianity begins with a triumphant indicative." J.G. Machen. Christ has died, and is risen again.
Why?
This is the question posed by the OP. Who is this person, and why does he and what he did matter to me? Why should I view him as my Glory? Why should I give up everything else that looks like it's worth something, for obtaining the least place in his kingdom?
"Why should I take up my cross, and follow him? That's what he said? Sounds like a losers game, to me."
Indeed.
No one is right with God. The "gospel" or "good news" implies that there's some bad news that needs a remedy. The letter of Romans is structured so that in the first place all men, of whatever origin or moral standing, are classed together in the category of the condemned. "The wrath of God is revealed" against them. If they are brought under conviction, then they may find hope in the fact that "the righteousness of God has been revealed" in the grace of the Lord Jesus Christ.
Anyone who will not have Christ on Christ's terms, does not understand his predicament. Jesus does not "go good with anything." He will not salt your stew. He demands your unconditional surrender. Jesus wouldn't cut a deal with anyone, and this is one factor that sealed his fate, so to speak, in earthly terms in the 1C. He was not a politician. He was not a negotiator. He is a King, and he acted like one with the powers he dealt with in this world long ago.
You need to see there's more than this world. Gain all of this, and lose your soul, and what does all this get you? The word and the way of the cross is foolishness to them that are perishing.
Why should you become a Christian? Because everyone should have a hero, and Jesus is the one only suitable. He is the Mediator: the Prophet, the Priest, and the King. And you need all three.