Shabbat Shuvah

In Igros Moshe (1:147), R' Moshe Feinstein discusses the proper formulation of the haftarah for Shabbos Shuvah, which appears in many chumashim as coming from Hoshe'a 14:2-10 (Shuvah Yisroel), Yo'el 2:15-27 (Tik'u shofar b'Tzion), and Micha 7:18-20 (Mi Keil kamocha nosei avon, etc.). He rejects the practice of reading all three sections, explaining, rather, that the proper haftarah is Hoshe'a and either Yo'el or Micha.

He then goes further to explain the reason for the two options. The section from Hoshe'a is the main part of the haftarah, beginning with an exhortation to do teshuvah. The only problem, though, is that the haftarah ends on a negative note (14:10):

מִי חָכָם וְיָבֵן אֵלֶּה, נָבוֹן וְיֵדָעֵם כִּי-יְשָׁרִים דַּרְכֵי יְהוָה, וְצַדִּקִים יֵלְכוּ בָם, וּפֹשְׁעִים, יִכָּשְׁלוּ בָם

"Whoever is wise, let him understand these things; whoever is understanding, let him know them: For the ways of Hashem are upright, and the righteous shall walk in them, but sinners shall stumble in them."

For this reason, we have to append an additional short passage from later in the book of T'rei Asar in order to end on a positive note. The best candidate for this would be the three-verse stand-alone section from Micha. However, this would not be a feasible option in shuls that read the haftaros from a Navi scroll, as the two sections are separated by the 25 chapters that comprise the books of Yo'el, Amos, Ovadiah, Yonah, and Micha, and to roll the scroll to this extent in the middle of the haftarah would constitute a tircha d'tzibbura. Therefore, shuls in this circumstance read the section of Yo'el, which is only one or two columns shifted over, and which, although it is considerably longer that the section from Micha, does not require "dead-time" in the middle of the haftarah.

As a bonus, the section from Yo'el when added to the section from Hoshe'a makes the haftarah longer than 21 pesukim, which is the theoretical minimum length for a haftarah (except when the topic of the chosen section of Navi ends before this minimum is reached, which happens surprisingly often).