It's interesting you bring up slavery. I think I should be allowed to sell myself or kill myself if I wanted to. I certainly don't want society or a government to regulate on that.

Eg. I'd rather be a slave than starving on the road, I'd rather be dead than in some particular irreversible painful medical condition.

The only actions which are ethically wrong in my book are hurting someone else or damaging / stealing their property. Incidentally the government breaks these rules legally everyday (eg. taxation, wars, spying on people).