Reason #827 You Know You're Crazy:
You're drowning in Jewish acronyms, but eventually they begin to make sense. Some of the acronyms I've found to be the most common include...
B"H: Baruch HaShem. Thank G-d.
B"H: B'Ezrat/Ezer HaShem. Means "With G-d's help." Some people write this at the top of letters/emails.
BS"D: B'si'ata d'shmaya. Means "With heaven's help." Some people write this at the top of letters/emails.
NOTE: I located an internet source that says the distinction is that B"H should only be placed at the top of a letter that is Torah-related, but that any other kind of letter, personal/business/otherwise, should use BS"D.
BT: Baal Teshuva. Refers to someone who becomes observant later in life.
FFB: Frum from Birth. Refers to someone who was raised observant.
MO: Modern Orthodox.
IY"H: Im Yitzeh HaShem. Means "If it be G-d's will," but many people say "G-d willing" in English.
R': Rabbi. Used before a rabbi's name.
Z"L: Zichrono Livrocho (male)/Zichronah Lebracha (female). Pronounced "zal." Means "Of blessed memory." Used behind someone's name to indicate that they are deceased.
ZT"L: Zecher Tzadik Livrocho. Pronounced "zatzal." Means "The memory of the righteous is a blessing." Used behind the name of prominent deceased Jews.
A"H: Alav/Aleha Hashalom. Means "Peace be upon him/her." Used behind someone's name to indicate that they are deceased. (In my experience, this is the least common of the acronyms used to note that someone has passed away.)
HY"D: HaShem Yikom Damo(am). Means "HaShem will avenge his(their) blood." Used to denote martyred Jews.
Other places you will see acronyms:
Synagogue names will often consist of several words (often because multiple synagogues have merged over time) and most people will refer to them by their acronym. (My personal favorite acronym-related place is "The Alphabet Shul" of West Orange, NJ: Congregation AABJ&D.)
Jewish organizations are also subject to acronymization. It's not quite an acronym, but I always enjoy calling our Jewish Federation the "JFed."
The sages sometimes have "names" that are actually acronyms. In fact, the acronym Chazal ("Our sages of blessed memory") is described by Wikipedia as: "In rabbinic writings, this is a general term that refers to all sages of the Mishna, Talmud, and other rabbinic literature commentators, and their authoritative opinion, from the times of the Second Temple of Jerusalem until the 6th century." Individual acronymized sages include: Rambam, Ramban, and Rashi.
We Jews love our acronyms!