"You have had five husbands, and the one you now have is not your husband" (John 4:18)
Ouch. Jesus lifted the veil of this woman's life. He exposed her folly. She was on her fifth husband, and the fifth one, He said, "is not your husband." Obviously, her perception of her life and God's perception of it, were different.
But that reality was quickly consumed by a popular social issue, and she departed from the subject of her personal sin. "Our fathers worshiped on this mountain, but you say that in Jerusalem is the place where people ought to worship" (John 4:20).
She's concerned about who's right, Jews or Samaritans. Jesus is just concerned about her tangle of sin.
Only when she dealt with her own sin, could she evaluate other situations clearly (cf. Mt. 7:5).
Gladly, her testimony about Jesus provoked many Samaritans to faith in Jesus as "The Savior of the world" (John 4:42).
There are endless religious questions. Some of them - like ones pertaining to acceptable worship - are very important. But no question is more important than "what about my sin?" This ought to be our focus in evangelism, and in our personal lives.