I read in some story that the way a transporter works is it actually kills you and reproduces a clone of you, complete with your former memories, every time it transports you. Sure, that was for purposes of that particular story, but it’s made me swear off transporters just in case.
Star Trek transporters always creep me out for that reason. You’re being killed. The new you doesn’t know he’s not you, but you’re dead. After 500 transports, what happens in the afterlife? Clone number 499’s soul shows up and sees the original and clones 1 through 498 talking about how they all died in transporters.
The continuity of the self is a fundamental problem for philosophy and neuroscience.
On the face of it, being teleported the star trek way involves a Person A being vaporised and a new Person B, who happens to be identical to Person A, being created. And furthermore, the common sense view is implicitly that Person A has been the same person / self / whatever since conception.
But this all rests on certain assumptions about the nature of the self that start to look quite flaky when we look at other hypotheticals like taking away parts of the brain or replacing parts of the brain bit by bit. And what about if we were to suspend all brain activity for a moment? Does the self persist through that?
I’m not trying to say there’s a soul or anything like that, I’m saying it may be the case that persistance of the self is an intuitive, but ultimately meaningless concept like free will.
On an up note, a software patch is all you need to have all the compatible donated organs you want!
Male contraceptive pill.
Spell checks for message boards.
Firefox. 
Or google chrome (in fact it just told me that google isn’t a real word as I typed this).
I am disaapointed that we don’t have :
-rayguns-that can kill without a noisy gunpowder explosion driving a bullet
-meals in a pill (“you will carry a week’s worth of steak in your wallet”)
-self-cleaning houses
-sheets of illumination materials (your walls all glow with a soft light)
-self-limitig growth grass (you don’t have to cut your lawn)
Alas, hsitory hasn’t panned out like a 1958 edition “Mechanix Illustrated”!
Question: Is Tom McCahill still alive? Haven’t read one of his car reviews in some time!
Even better, an intra vas device: something simple to implant and reversible.
No Mow Grass exists! http://nomowgrass.com
How about a cellphone that gets better reception? I mean, I had analog cellphones in the 90’s that hold calls better than what we have today - it’s like they’ve gone backwards since going digital…
Don’t like Firefox. Or at least, my computer doesn’t. 
Get a Mac. Everything is automatically spell-checked in every application and all browsers.
So I somehow have ended up with the one type of computer and types of applications that don’t spellcheck. Great.
Fifteen years ago I there were some piddly little cordless circular saws appearing. I rolled my eyes with the uselessness of the idea. About four years ago I bought a Makita 3Ah lithium set. The 6.5" circular saw it came with was very high quality. I thought “this might actually be useful”. I bought a new 7.25 corded saw the same day, it sits in the same dusty drawer as the old one, only taken out when I am framing. I use the little cordless one every day, along with the recip saw, angle ginder, impact driver and hammer drill it cam with. Those batteries are nearly four years old and still going strong. Awesome.