This story I heard from Rabbi Yisroel Gordon and it has been printed in Taharas Mayim by Rabbi Telushkin.
Once there was a person who wanted to be with the Magid for Pesach. He set off in his horse and buggy and when he was most of the way to Mezritch his horse fell into a ditch. The man climbed out and ran to the nearest village for help. The local Jewish innkeeper was able to help, but in rescuing his horse, the man ran out of time to get to Mezritch and he was very upset because after all this time and effort getting to the Magid, he was stuck in a village. The innkeeper tried to comfort him by saying thank G-d you got stuck in a village where there are Jews!
What would have happened if you were stuck among non-Jews for Pesach!!
The man saw that the innkeeper was right. Therefore, he calmed down and spent Pesach with these people. He saw they had a minyan, they made Sedarim, but he saw something peculiar about their recitation of the Haggadah. When they read of the simple son who asks “ma zos” “what is this,” everyone began to cry and when they continued with the response “that with a strong arm Hashem took us out of Egypt,” everyone said it with great joy. This happened on both seder nights. The man didn't want to question his host, the innkeeper; instead he waited until after Pesach when he continued on his way and finally got to Mezritch.
The Magid asked him where he was for Pesach and the man described his entire journey and all of his adventures. Then he turned to the Magid, “I have a question.” Then the man told the Magid the whole story about recitation of the Haggadah and the simple son – why was everyone crying by “Mah zos” and why was everyone joyous by the answer?
The Magid responded that every mitzvah we do Hashem does Himself, as it says, “He tells His words (Torah) to Yaakov and His commandments and laws to Israel” (Tehillim 147). So when Hashem tells us to do a mitzvah, he also does a mitzvah. We make a seder down here, and similarly, Hashem is making a seder Up There. (See Likutei Sichos, vol. 3, the Rebbe's explanation on הא לחמא עניא). So when they were saying תם מה הוא אומר... “The simple son, what does he say...” they interpreted taam to mean over there (in Russian; and in Aramaic taamon means over there). So what were these people saying? Taam, ma hu omeir? Over there what is Hashem saying? Ma zos – what is this? I sent you into this world to serve Me and to make this world a dwelling place for Me but you got involved with your worldly desires and you forgot the purpose of your mission. All the people at the Seder were crying because Hashem had a good complaint. The Hagadah continues, “ואמרת אליו” “You should say to Him (to Hashem) that You took us out of Egypt with a strong arm. Even though we had sunk into the 49th level of impurity in Egypt, and even though the supervising angel of Egypt complained that the Jews were serving idols, and they were no different then the Egyptians, still You used Your forceful arm and pushed all the complaints aside and redeemed Bnei Yisroel because the time for their redemption had arrived. The same thing now, we are telling Hashem don't ask any questions just take us out of golus now! This is why the innkeeper and his family were so joyous.