This is tricky. One of my head canons is that most ghosts think the afterlife is the best thing ever once they adjust to it, and they'll gladly "help" other Sims shuffle off the mortal coil. I've also got a rule that too much interaction with ghosts zaps away a Sim's lifeforce, putting them more at risk for accidents.
So, yeah, I like the drama that ensues when a Sim joins the ghosts against their wishes. But I also don't treat death like a permanent thing, either.
I've never let a Sim starve, and only two have drowned. I felt uncomfortable watching both of those. I almost always do it via emotions or cowplant. Sometimes fire or electrocution if them having fire-starting or electronic-breaking powers is relevant to the plot. Deaths are easier to watch if the Sim was mean to others.
Anytime I've sent a ghost to the Netherworld, it's been an emotional moment. Usually their character arc is complete, and they're ready to move on.