"U do whatever ATC say"... if U can, if your aircraft can & above all if U agree : as the pilot, U are the final authority, not ATC. Eg I wouldn't bother with the STAR if I had an engine problem ! In addition, to accept a STAR, U need to have a description of it in front of U. ATC want U to fly a STAR & U don't want to : very simple : just say "unable to comply, requesting RV". U can also mention "no STAR" in the flight plan & they won't issue U with one.
MF