Builder safety worry

in 2003 i engaged a builder to extend my property.

1-when I asked for 3 light switches to control 1 light, it took him a week to find out how to do it....he ran multiple cables , just in case, until he found out how it should be done...
2-he fitted a consumer unit, but immediately it kept tripping every time an appliance was used.....this went on for many many many hours, eventually he disconnected some protection within the box, think it looked for difference between live and neutral, he said it wasn’t needed anyway, after 2-3 years it suddenly started emitting smoke.....I called an electrician and he said it had been wired up wrong and replaced it completely...
3-today I removed some flooring and skirting board in my spare room, for decorating and a plumbing change, but found he had used a domestic light switch as a junction box below the floorboards and behind the skirting I found a 2.5 cable supplying a socket running behind the skirting, it had a connecting block joining it to another cable, which was buried into the floorboard.

In my builders defence, he once said to me, when I enquirer about an electrical issue “ well I am not an electrician” says it all I guess, I should have said, get a real one then, but at the time tensions were high and the the extension was taking far longer than expected and costing a lot lot more, so couldn’t afford to rock the boat......I wonder what other surprises await me in the future.......

Is my experience typical ?......scares the hell out of me

Thanks Alex rybak whereever your are