A Transporter system, a la, "Beam me up Scotty!"
Almost all ideas have been ones that I thought "yeah, that would be really cool!"
Yours is the only one where I would NEVER want that and would be terrified if it existed in real life. Tearing me apart into my component parts and rebuilding me? No thanks!
We already know from Riker and other transporter "accidents" that it's very possible to make 2 of someone, and for both of them to think they're the "real" person. So fundamentally, if you walk into a machine thinking it'll spit you out elsewhere, and you find yourself elsewhere, all from your perspective seems fine. How do we know, though, that the thing that pops out of the other side is truly you, and not some entirely new being that carries with it your mind, experiences, personality etc?
What if upon using a transporter you are utterly destroyed, and some new thing walks around in your life wearing your skin and mind, with no one the wiser? That to me seems like the FAR more likely scenario, and it would be impossible to ever truly know, as the original creature would not still be around to complain about it. If a transporter existed, I just know that I sure as hell would never use one.