Bummer. Agreement didn't last long.
Have you read the story in context? Jesus wasn't being nice, He was telling the Samaritan that the day was coming when it wouldn't only be Jews worshiping God in the Temple but all people worshiping in all places (in Spirit and Truth).
He was telling the Samaritan of the prophecy given by Isaiah 56:7.
4 For this is what the Lord says:
“To the eunuchs who keep my Sabbaths,
who choose what pleases me
and hold fast to my covenant—
5 to them I will give within my temple and its walls
a memorial and a name
better than sons and daughters;
I will give them an everlasting name
that will endure forever.
6 And foreigners who bind themselves to the Lord
to minister to him,
to love the name of the Lord,
and to be his servants,
all who keep the Sabbath without desecrating it
and who hold fast to my covenant—
7 these I will bring to my holy mountain
and give them joy in my house of prayer.
Their burnt offerings and sacrifices
will be accepted on my altar;
for my house will be called
a house of prayer for all nations.”
8 The Sovereign Lord declares—
he who gathers the exiles of Israel:
“I will gather still others to them
besides those already gathered.”
He’s talking about the B’nai Noach.