The following word and phrases share an unusual quality which has nothing to do with their meanings. Can you determine what it is?

UNITARIAN CHURCH
GOES UNDERGROUND
INSUFFICIENCIES
TATTERED AND TORN
STRENUOUS EFFORT

HINT:
It has to do with the letters in each clue.

Answer:

In each clue, each letter is repeated twice, except for one letter.

Credit: NY Times Crossword - May 31, 2009
Kelsey Blakley
ODD ONE OUT