sensitive
insensitive (remember that it's a false friend!)
patient
impatient
concerned
unconcerned (=not worried)
popular
unpopular
able
unable
predictable
unpredictable
known
unknown
responsible
irresponsible
reasonable
unreasonable
experienced
inexperienced
comfortable
uncomfortable
mature
immature
cooperative
uncooperative
accessible
inaccessible
enthusiastic
unenthusiastic
organised
disorganised
acceptable
unacceptable
reliable
unreliable
willing
unwilling
successful
unsuccessful