person  things
A   TV
A   CAR
A   MOBILE
A   HOUSE
B   TV
C   TV
C   CAR
C   MOBILE
C   HOUSE
D   TV
E   TV
F   TV

SELECT things
FROM tbl_happiness as x
WHERE NOT EXISTS
(
SELECT person
FROM tbl_happiness as y
WHERE NOT EXISTS
(
SELECT 1
FROM tbl_happiness as z
WHERE z.person = y.person
AND z.things = x.things
 )
);