Q: Is it bad luck if a black cat crosses in front of me?
A: It is a superstition and believing in it violates the prohibition of sorcery. Rambam, Hilchot Avodah Zarah 11:4.
Q: I read in Sefer Ha-Kaneh that it is forbidden to kill a black cat.
A: It is not quoted in the Halachah books. Regarding the issue of a black cat, see Ain Aya of Maran Ha-Rav Kook, Berachot Chapter 1 #47 (see Ner Be-Ishon Laila pp. 149-150).
Davening in the Wrong Direction
Q: After I finished Davening Shemoneh Esrei, I realized that I did not Daven in the direction of Yerushalayim. What should I do?
A: You fulfilled your obligation (Be'er Heitev #94. Shut Meishiv Davar 1:10. Shut Teshuvot Ve-Hanhagot 1:79).
Being Stricter than Your Rabbi
Q: Is it permissible to follow a Chumra which one's Rabbi does not?
A: Only in private, on account of "Yehura" – religious arrogance. See Baba Kamma 81a (The author of the Kochav Mi-Yaakov once asked the Admor of Hosiatin why he did not prepare all of his water before Pesach to avoid any potential problems of Chametz. He said that he learned this from what the author of the Degel Machaneh Ephraim said: That since the Baal Shem Tov was lenient, he does not act strictly. He then asked: What does one lose by being strict, since it is proper to add another stricture on Pesach? He replied that this is incorrect based on the Gemara in Beitza 36a that Abaye was punished for acting stricter than his Rabbi, Rabbah. However, in the biography of the Arugat Ha-Bosen, it is told that he was strict to learn with his hat on even on extremely hot days. He was asked: Why cause yourself distress? Didn't the Ketav Sofer – your teacher – learn without his hat? He responded: Is it forbidden to be stricter than one's Rabbis?! Commentary on Pirkei Avot 'Az Yomru' of Ha-Rav Yitzchak Aharon Goldberger, Dayan and Rosh Yeshiva for Pupa Chasidim, pp. 74. And see Shut She'eilat Shlomo Vol. 4, p. 285 regarding one who is strict in a place where it was decided to be lenient).
Mother or Rashbi
Q: I visit Kever Rashbi every Rosh Chodesh but my family is moving this Rosh Chodesh and I assume that my mother would be happy if I stayed, although she did not ask me to do so. Which is preferable?
A: Certainly honoring your mother, which is an explicit Mitzvah in the Torah and is in the Ten Commandments. Visiting the Kever of the Rashbi does not have a source in the Torah, the Mishnah, the Gemara or in the halachic codes, and is thus not as important as a Torah Mitzvah (See Moed Katan 9:1-2. Rambam, Hilchot Talmud Torah Chapter 3. And Hilchot Maamrim 6:13).
Writing during a Life-Threatening Situation on Shabbat
Q: If one is obligated to write on Shabbat during a life-threatening situation, in the case of a doctor or soldier, is it preferable to use a pen or computer?
A: Computer, since writing with a pen or pencil is a Torah prohibition while writing on a computer, which involves electricity, is a Rabbinic prohibition (see Kishrei Milchama of Colonel Ha-Rav Eyal Krim 3:41).
Love of Hashem
Q: How do I work on loving Hashem?
A: See Mesilat Yesharim Chapter 9.
Q: My mother is Yemenite and my father is a non-Jew from Switzerland. Am I Yemenite or Ashkenazi?
A: Yemenite. From a halachic perspective, the non-Jewish father's seed is not considered.