Papi and I were out to eat one evening.
A couple next two us with two young childre were having their dinner.
Those children sat in their chairs, ate their dinner, said please and thank you, and were very very well behaved.
Behind us was another family with three small children.
These children were running up and down the aisles, chasing each other, screaming and holler and acting the general fool while the parents sipped their wine, ate their dinner, and socialized.
The difference? The parents. You get what you expect.
If you expect your children to behave in public, they will.