This expression may have originated in Scotland, where it's the title of a popular children's song. A song called "Everything Is Tickety-Boo" was recorded by Danny Kaye as part of the film "Merry Andrew".
This expression is heard more often in Canada nowadays. May have originated in the British military. Possibly related to the Hindi expression "tickee babu", meaning "everything's alright, sir". Some people spell it "diggity boo" or "tiggity boo".
Everything is tickety-boo, tickety-boo, tickety-boo...
Also means "I, with God's help" or "I, with God-in-me". Often used in place of "me". Because the people's Identity was destroyed in slavery, Identity is very important in RastafarI -- so I gets capitalIzed a lot. They pronounce the I's strongly in reggae songs. Emperor Haile Selassie I is not "the First" but "Haile Selassie *I*."
I and I build the cabin
I and I plant the corn
Didn't my people before me
slave for this country?
As stated above, "fanservice" came from Japanese anime, film, and music culture. Its definition is spreading to include any unnecessary visuals included simply because the fans, presumably, want to see them. Gratuitous nudity, male or female, but also shots of cute mascot animals (e.g., Chuchu the mouse in "Utena").
Jay (watching a Chinese wuxia film): They just spent ten minutes showing us Alec Su taking a bath.