Each of the clues below can be answered with a familiar phrase - plus two letters at the end of one of the words in the phrase. The two added letters are the same for each answer, and modify the phrase to answer the clue.

1. Failure to get upgraded to first class
2. Roster of most-stressed people
3. Links language
4. Expert handler of barnyard fowl
5. Twins who claim to be Norwegian, but aren't
6. Hot and desperate shopping look-around
7. Betting without thinking
8. Polite request to a seller to negotiate on price
  
Answers:

The two added letters are SE.

1. LAPSE OF LUXURY
2. TOP TENSE LIST
3. GOLF PROSE
4. GEESE WHIZ
5. NEITHER NORSE
6. FEVERED BROWSE
7. GAMBLING DENSE
8. PLEASE BARGAIN

Credit: Arlan and Linda Bushman
SOUTHEASTER DIRECTION (adapted)