1. What do the following words have in common?

ORIGINAL
TENDON
STATISTICIAN
COMFORTED
BETRAY
JETSAM

2. What do the following words have in common?

SON
STOP
NOSE
DROP
GROVE
CARTON

HINT:
1. It has to do with the ending letters of each word.

Answers:

1. The last two or three letters of each word can be a man's name. 

originAL
tenDON
statisticIAN
comforTED
betRAY
jetSAM

2. Doubling the O in each word creates a new word:

SOON
STOOP
NOOSE
DROOP
GROOVE
CARTOON