Both their functionings are complex, so people can get impressed. But for both of them, all the complexity is inside the device and there isn’t much to put together; and the way they hook up to your house is really simple.
Why YSK: so you don’t live too long with a broken toilet or garbage disposal, thinking it will be too hard to replace. Those two are some of the simplest things to DIY.
I bought and broke a few tools trying to remove the bolts, and WD-40 didn’t do jack for my rust problems, so I also ended up having to buy a mini hack saw and extra bolts. It was still an interesting endeavor. I would still do it myself again.