It sucks because when someone who you never really got along with says some BS at your funeral you can't suddenly stand up in the casket and yell "Shenanigans". What you should do is have a list of people that only mattered to you and give it to your parents, SO, children, whoever. Then, record yourself saying something "Shenanigans" or "Bullsh!t! We never got along!". Then at the funeral, have them put a speaker in your casket, and when the person you don't like says something nice about you, have the person with the list play the audio file.
Everyone would probably get to gather around at another funeral if that went off successfully, because I'm sure someone would have a heart attack.