I notice this a LOT more in Thailand than anywhere else I’ve been. Whenever I order food – in English or in Thai – the order is frequently wrong. It’s not usually just a little wrong, it’s usually completely wrong.
It’s not like I ordered with regular rice and I got sticky rice. It’s more like I ordered Som Tam and I got Pad Thai.
Best response? If you can eat it – eat it. The waitress will lose face if you return the item. Next time you have that waitress/er make sure they repeat back what you ordered.