And electrical

It's got a much higher bar to do it properly because they are a lot of safety factors and correct ways to spec and install stuff, and sloppy work will burn your house down. And a lot of that is non obvious, and different countries have their own ideas about how to do things (like we use a ring circuit) But if you are just modifying existing circuits and are super neat about wiring then it's mostly OK.

Having seen the god awful shit I've pulled out of walls from "professionals", then they are all clearly working down to a price point, and I've got all day to do it right, so I'm happy that my wiring is better.

And it's nice coming back to repair a damaged socket remembering that you left a bit of slack there for the next guy, and it happened to be me.

Same for plumbing, I'm happy coming back to my jobs because I know I've added cut off valves to everything so every fix is going to be easy. Unlike the last "professional" who somehow managed to install full central heating without an apparent drain valve anywhere...?

Throw a cat in the bathtub along with the toaster