PROCESS OF ELIMINATION
Credit: NY Times Crossword
Patrick Berry

The answers to the clues below share a very unusual quality. Can you determine what it is? But wait! There's more! The first clue has been left out at this point, but will be given below. The answer to this clue, combined, in order, with the other answers, will give the theme of this puzzle.

2. Sticks in the medicine cabinet
3. Forbidding countenance
4. Lacking compassion
5. "It's true, like it or not" metaphor
6. British motorist's right
7. 1999 romantic comedy based on "Pygmalion"8
8. It's taken by doctors
9. Follow-up to a potential insult

Answers:

2. ANTIPERSPIRANTS
3. HATCHET FACE
4. HARD HEARTED
5. "IF THE SHOE FITS"
6. DRIVER'S SIDE
7. SHE'S ALL THAT
8. HIPPOCRATIC OATH
9. "NO OFFENSE"

HINT FOR THE UNUSUAL QUALITY:
It has to do with the letters in each clue.

Unusual Quality Answer:
In each clue, each letter is repeated twice, except for one letter. 

FIRST CLUE:

1. "I quit. You're all cheaters. I'm taking my ball and going home."

This clue follows the same pattern as the others, but with one additional distinctive feature. The excepted letter is exactly in the middle of the phrase that answers the clue. The repeated letters are evenly split on either side of the excepted letter.

Answer to first clue:

1. SORE LOSER

Now determine the single letter that is not repeated in each answer, beginning with L in the first clue. These letters, read downward, reveal the theme of this puzzle.

THEME ANSWER:

L
E
F
T
O
V
E
R
S