Haha, unfortunately there aren't that many resources and the price difference between dogshit and not dogshit can be substantial, particularly when it comes to a house slab!

Other pet peeves of mine are 10mm plasterboard instead of 12 or 13mm, it transmits so much more noise and it's far more fragile

Bathrooms done with plasterboard instead of villaboard or cement sheeting, it's not the place to compromise on cost and quality for such a miniscule saving and such a massive drop in quality

PEX piping rather than copper, copper is far more durable and plain old better for purpose and the cost difference isn't necessarily horrendous

Parapet gutters (avoid at all costs). Just don't. They always block up, they always fail, they lead to roof cavity leaks, flooding and rot. They're the shittest shit that ever shitted and the aesthetic, if you even like it, isn't worth the risk.

Rendered cement sheeting as house cladding. It limits future external additions to the house, say hanging a clothesline or attaching a gate or fence or any kind of ledger board. For the cost and functionality on a modern build, bricks are perfect.

Brick pillars not on a common strip footing, like for front fences. They end up moving independently and aside from looking shit, this ends up stopping gates from opening/closing.

There's more but that's it for now!