I have long maintained that the best way to kill someone and get away with it is to push them off a cliff.
While hiking, for example. It’s simple, clean, no need to dispose of evidence, and proving beyond a reasonable doubt in a court of law that the deceased didn’t just fall off the cliff accidentally is almost assuredly impossible.
Unfortunately, the opportunity to push someone off a cliff is no longer on the table for me, having published in advance my admiration for cliffs as a murder weapon, but I’ve got other ideas as well.
That said, the worst way to murder someone is to take them on a cross-country road trip, document the whole thing on social media, then drive home by yourself and disappear.