The following eight words can be grouped into four pairs according to a certain rule. Can you determine the rule and pair up the words properly?

ANNOY
ORE
TENNIS
ILL
ETIQUETTE
GONE
CON
SEA

HINT:
#1: It has to do with the phonetic sounds of the words.
#2: Think US geography

Answer:

The words should be paired so that when each pair is read together, it sounds like the name of a state:

ILL-ANNOY (Illinois)
ORE-GONE (Oregon)
TENNIS-SEA (Tennessee)
CON-ETIQUETTE (Connecticut)